title: Why are date values "slipping through" a filter in Excel?
body: <p>I'm cleaning data in Excel that has a date column with mm/dd/yyyy values mixed with dd/mm/yyyy values where the former are date formatted and the latter are general formatted. The way I'm doing this is to filter out everything that's date formatted (ie: shows up in the filter as 1964 -> March -> 27, etc... at various levels), leaving only those that are general formatted (shows up in the filter as as 27/03/1964). When I do this, I find that there are still date-formatted cells visible. I'm wondering why this is? Is it a consequence of how the filter works or how Excel reads date values?</p>