user1908: Some cleanup tasks need to be done on an ongoing basis as new questions/answers/etc introduce cruft to the site. 
The aim of this question is to compile a list of tasks that:

Fall outside the scope of the standard review queues
Need to be done to keep the site nice and shiny


I now maintain another version of this post over at Meta.Hinduism.SE. 

user1908: Note that though all users may propose edits, you must have a certain amount of reputation for your edits to go through immediately without review - 1000 rep for edits to questions/answers, and 4000 rep for edits to tag wikis.
Answering

Answer unanswered questions! - Given that this is a question-and-answer site, perhaps the most unseemly thing would be for us to have a large number of questions without answers. Scroll through this list every so often (perhaps looking only at questions in tags where you've already answered a number of questions) and see if you can't answer a question that hasn't been answered.

General editing

Handle questions that need retagging - Some questions end up tagged with retag or untagged. If these questions are on their way to deletion, you can just leave them be, but if not (e.g. if they are closed as a duplicate or something), you should assign an actual tag to the question. 
Find questions that could probably use copy-editing - This query uses a number of proxies for finding posts that could probably do with being overhauled in terms of capitalization, spelling, grammar, etc. 
Find questions that use code formatting - There are some legitimate uses for code formatting (e.g. simulating tables), but they are few and far between on this site, since this isn't a programming-related site. Users often incorrectly use code formatting when they should use quote formatting; use this query to identify those instances and clean them up.
Find questions and answers containing Google redirect links - Occasionally, users may copy-pasta links directly from Google search result, which are turned into a big mess of redirect link courtesy of Google. Edit all those redirect links into direct link to the intended page.

Salvaging

Evaluate questions with existing deletion votes (requires 2000+ rep) - This is part of the standard set of moderation tools, and allows you to see questions that have received at least one deletion vote in the past 30 days. If you think the question should be deleted, cast your vote. If you disagree, leave a comment explaining why or otherwise make the question better. You can also look at questions that have recently been deleted and cast undelete votes where appropriate. In general, you should only vote to delete posts that are either 1) very old and reasonably bad; or 2) egregiously bad and utterly beyond salvation.
Evaluate questions and answers with existing deletion votes (Data Explorer) - Same as above.
Preemptive evaluation of questions in danger of automatic deletion - Review the question and see whether the question is worth keeping on our site. If you think the question is good, upvote the question to minimal threshold (score +1 for question with owner, score +2 for question without owner). If the question has already passed the threshold, there is no need to force yourself to upvote it if you find it mediocre. Do not blindly upvote/downvote everything in the list

Tag wikis and excerpts

Find tag wiki excerpts that probably contain markdown - Since the page for editing a tag wiki doesn't include a preview for the excerpt, some users will use markdown (mostly italics) and expect it to render correctly. However, tag wiki excerpts do not permit any sort of markdown. Click through the links in this query and edit out any markdown you find in the excerpts (and fix anything else you find while you're there!). The query should also catch furigana formatting (e.g. 日本​{にほん}), which will render successfully in the excerpts (since it's client side) but will also mess up spacing, and hence should not be used anyway.
Find empty tag wiki excerpts - All tag wiki excerpts should have something in them, even if it's as straightforward as "[series name] is a [anime/manga/etc] by [author]". 
Find long tag wiki excerpts - Tag wiki excerpts should be reasonably concise. Look over this query and remove excess verbiage from excerpts if you can do so without making the excerpt unclear. Pay particular attention to those that have a "YES" in the "Truncated?" column.

Images

Find images that aren't hosted on imgur - Users sometimes hotlink images from other sites in their questions and answers, which can be a problem for us if the hotlinked site takes down the images at some point. These images should be rehosted on stack.imgur.com (hit Ctrl+G when editing). Note that this query won't catch images hosted on sites beginning whose URLs begin with the letter i, e.g. imageshack.
Add alt-text to images that don't have it - for the sake of accessibility/searchability/whatever, it is generally helpful to have some sort of alt-text for images. Click through the posts in this query and add alt-text to any images that don't have any.

Japanese-related

Find macrons and circumflexes in titles - We've found that questions containing words with macrons (e.g. Yūji, Kyōko, etc.) don't tend to show up when people google for the un-macron'd words (resp. Yuuji/Yuji and Kyouko/Kyoko), which makes for bad SEO. Macron-containing words in titles should be respelled to avoid the use of macrons.
Find posts that use {} for furigana - Mobile users are better served by furigana that uses 【】 rather than {} whenever feasible, since the former is significantly more readable inline. 

Comment cleanup

Find comments that might be obsolete - While I'm not a fan of aggressively deleting comments, some comments are obviously obsolete and not worth keeping around - for example, comment chains that go like "You should include this fact in your answer" / "I have included this fact, thanks". Look through the comments shown in this query, and evaluate which of them should be flagged as obsolete. This query is not perfect - do not go through and flag all of them willy-nilly!

Miscellaneous

View recent edits to tag wikis and excerpts - In the absence of a built-in way to sort tags by most-recently-edited, this is a kludge to emulate that in SEDE. 


1908: <p>Some cleanup tasks need to be done on an ongoing basis as new questions/answers/etc introduce cruft to the site. </p>

<p>The aim of this question is to compile a list of tasks that:</p>

<ul>
<li>Fall outside the scope of the standard review queues</li>
<li>Need to be done to keep the site nice and shiny</li>
</ul>

<hr>

<p>I now maintain <a href="https://hinduism.meta.stackexchange.com/q/186/13">another version of this post over at Meta.Hinduism.SE</a>. </p>
 1908: <p>Note that though all users may <em>propose</em> edits, you must have a certain amount of reputation for your edits to go through immediately without review - 1000 rep for edits to questions/answers, and 4000 rep for edits to tag wikis.</p>

<h2>Answering</h2>

<ul>
<li><a href="https://anime.stackexchange.com/unanswered/tagged/?tab=newest"><strong>Answer unanswered questions!</strong></a> - Given that this is a question-and-answer site, perhaps the most unseemly thing would be for us to have a large number of questions without answers. Scroll through this list every so often (perhaps <a href="https://anime.stackexchange.com/unanswered/tagged?tab=mytags">looking only at questions in tags where you've already answered a number of questions</a>) and see if you can't answer a question that hasn't been answered.</li>
</ul>

<h2>General editing</h2>

<ul>
<li><a href="https://anime.stackexchange.com/questions/tagged/untagged+or+retag">Handle questions that need retagging</a> - Some questions end up tagged with <a href="https://anime.stackexchange.com/questions/tagged/retag" class="post-tag" title="show questions tagged &#39;retag&#39;" rel="tag">retag</a> or <a href="https://anime.stackexchange.com/questions/tagged/untagged" class="post-tag" title="show questions tagged &#39;untagged&#39;" rel="tag">untagged</a>. If these questions are on their way to deletion, you can just leave them be, but if not (e.g. if they are closed as a duplicate or something), you should assign an actual tag to the question. </li>
<li><a href="http://data.stackexchange.com/anime/query/201240/cleanup-find-posts-that-could-probably-use-some-copy-editing" rel="nofollow noreferrer">Find questions that could probably use copy-editing</a> - This query uses a number of proxies for finding posts that could probably do with being overhauled in terms of capitalization, spelling, grammar, etc. </li>
<li><a href="http://data.stackexchange.com/anime/query/203954/cleanup-find-code-formatting" rel="nofollow noreferrer">Find questions that use code formatting</a> - There are some legitimate uses for code formatting (e.g. simulating tables), but they are few and far between on this site, since this isn't a programming-related site. Users often incorrectly use code formatting when they should use quote formatting; use this query to identify those instances and clean them up.</li>
<li><a href="http://data.stackexchange.com/anime/query/303982/posts-containing-google-redirect-links" rel="nofollow noreferrer">Find questions and answers containing Google redirect links</a> - Occasionally, users may copy-pasta links directly from Google search result, which are turned into a big mess of redirect link courtesy of Google. Edit all those redirect links into direct link to the intended page.</li>
</ul>

<h2>Salvaging</h2>

<ul>
<li><p><a href="https://anime.stackexchange.com/tools?tab=Delete&amp;daterange=last30days"><strong>Evaluate questions with existing deletion votes</strong></a> (<strong>requires 2000+ rep</strong>) - This is part of the standard set of moderation tools, and allows you to see questions that have received at least one deletion vote in the past 30 days. If you think the question should be deleted, cast your vote. If you disagree, leave a comment explaining why or otherwise make the question better. You can also look at questions that have recently been deleted and cast <em>undelete</em> votes where appropriate. In general, you should only vote to delete posts that are either 1) very old and reasonably bad; or 2) egregiously bad and utterly beyond salvation.</p></li>
<li><p><a href="http://data.stackexchange.com/anime/revision/320023/414049/list-of-posts-with-pending-delete-votes" rel="nofollow noreferrer"><strong>Evaluate questions and answers with existing deletion votes</strong></a> (Data Explorer) - Same as above.</p></li>
<li><p><a href="http://data.stackexchange.com/anime/query/303966/posts-in-danger-of-automatic-deletion" rel="nofollow noreferrer"><strong>Preemptive evaluation of questions in danger of automatic deletion</strong></a> - Review the question and see whether the question is worth keeping on our site. If you think the question is good, upvote the question to minimal threshold (score +1 for question with owner, score +2 for question without owner). If the question has already passed the threshold, there is no need to force yourself to upvote it if you find it mediocre. <strong>Do not blindly upvote/downvote everything in the list</strong></p></li>
</ul>

<h2>Tag wikis and excerpts</h2>

<ul>
<li><a href="http://data.stackexchange.com/anime/query/175431/cleanup-find-markdown-in-tag-wiki-excerpts" rel="nofollow noreferrer">Find tag wiki excerpts that probably contain markdown</a> - Since the page for editing a tag wiki doesn't include a preview for the excerpt, some users will use markdown (mostly italics) and expect it to render correctly. However, tag wiki excerpts do not permit any sort of markdown. Click through the links in this query and edit out any markdown you find in the excerpts (and fix anything else you find while you're there!). The query should also catch furigana formatting (e.g. <code>日本​{にほん}</code>), which will render successfully in the excerpts (since it's client side) but will also mess up spacing, and hence should not be used anyway.</li>
<li><a href="http://data.stackexchange.com/anime/query/198067/cleanup-find-tag-wikis-with-blank-excerpts" rel="nofollow noreferrer">Find empty tag wiki excerpts</a> - All tag wiki excerpts should have <em>something</em> in them, even if it's as straightforward as "[series name] is a [anime/manga/etc] by [author]". </li>
<li><a href="http://data.stackexchange.com/anime/query/200384/cleanup-find-long-tag-wiki-excerpts" rel="nofollow noreferrer">Find long tag wiki excerpts</a> - Tag wiki excerpts should be reasonably concise. Look over this query and remove excess verbiage from excerpts if you can do so without making the excerpt unclear. Pay particular attention to those that have a "YES" in the "Truncated?" column.</li>
</ul>

<h2>Images</h2>

<ul>
<li><a href="http://data.stackexchange.com/anime/query/180619/cleanup-find-images-not-hosted-on-imgur" rel="nofollow noreferrer">Find images that aren't hosted on imgur</a> - Users sometimes hotlink images from other sites in their questions and answers, which can be a problem for us if the hotlinked site takes down the images at some point. These images should be rehosted on <code>stack.imgur.com</code> (hit <kbd>Ctrl+G</kbd> when editing). Note that this query won't catch images hosted on sites beginning whose URLs begin with the letter <code>i</code>, e.g. imageshack.</li>
<li><a href="http://data.stackexchange.com/anime/query/189404/cleanup-find-images-without-proper-alt-text" rel="nofollow noreferrer">Add alt-text to images that don't have it</a> - for the sake of accessibility/searchability/whatever, it is generally helpful to have some sort of alt-text for images. Click through the posts in this query and add alt-text to any images that don't have any.</li>
</ul>

<h2>Japanese-related</h2>

<ul>
<li><a href="http://data.stackexchange.com/anime/query/180823/cleanup-find-seo-unfriendly-romanizations-in-titles" rel="nofollow noreferrer">Find macrons and circumflexes in titles</a> - We've found that questions containing words with macrons (e.g. Yūji, Kyōko, etc.) don't tend to show up when people google for the un-macron'd words (resp. Yuuji/Yuji and Kyouko/Kyoko), which makes for bad SEO. Macron-containing words in titles should be respelled to avoid the use of macrons.</li>
<li><a href="http://data.stackexchange.com/anime/query/196749/cleanup-find-furigana-that-uses-curly-braces" rel="nofollow noreferrer">Find posts that use {} for furigana</a> - Mobile users are better served by furigana that uses 【】 rather than {} whenever feasible, since the former is significantly more readable inline. </li>
</ul>

<h2>Comment cleanup</h2>

<ul>
<li><a href="http://data.stackexchange.com/anime/query/201239/cleanup-find-comments-that-are-probably-obsolete" rel="nofollow noreferrer">Find comments that might be obsolete</a> - While I'm not a fan of aggressively deleting comments, some comments are obviously obsolete and not worth keeping around - for example, comment chains that go like "You should include this fact in your answer" / "I have included this fact, thanks". Look through the comments shown in this query, and evaluate which of them should be flagged as obsolete. This query is not perfect - do not go through and flag <em>all</em> of them willy-nilly!</li>
</ul>

<h2>Miscellaneous</h2>

<ul>
<li><a href="http://data.stackexchange.com/anime/query/199825/view-recent-edits-to-tag-wikis-and-excerpts" rel="nofollow noreferrer">View recent edits to tag wikis and excerpts</a> - <a href="https://meta.stackexchange.com/q/232332/224428">In the absence of a built-in way to sort tags by most-recently-edited</a>, this is a kludge to emulate that in SEDE. </li>
</ul>
