How to clear the cache or do a hard refresh in Safari?
Go to Safari &gt; Empty Cache, or hit ⌘ Command+⌥ Option+E. To refresh, click the refresh button on the addressbar or press ⌘ Command+R.

Another tip. If you want to restore Safari, like completely clear all the caches, or parts of it, go to Safari &gt; Reset Safari. I use it usually when I need to clear a lot of memory from Safari, for it will clear the webpage screenshots, the cookies, the favicons, etc. 



Edit: On the latest version of Empty Cache isn't on the Safari menu any more. It's now on the Develop menu. To show the Develop menu it, go to Safari &gt; Preferences..., click the Advanced tab, and check Show Develop menu in menu bar. The keyboard shortcut remains unchanged, though.

Safari &gt; Reset Safari isn't an option any more. To clear history you can use History &gt; Clear History... and to clear cookies/local storage data, go to Safari &gt; Preferences..., click the Privacy tab, and either click Remove All Website Data... or Details... to view and remove it for individual sites.