Why was I not able to edit a question
Who will clear my edits? and by when?
You may only submit up to 5 suggested edits at a time; beyond this, you will receive the message in your image.
The following users can review your edits:
When your edits get reviewed depends on when one of the above users notices your edits and reviews them; generally, it takes a couple of hours, but it is sometimes a little quicker or slower, depending on timezones.
An aside: removing thanks is great, but is best done sparingly for old posts to avoid disrupting the home page too much. If there are substantial edits to be made, great. Otherwise, editing just to remove thanks on an old post may not be the best use of your editing time — there are always new questions in need of editors, and your skills might be best spent there. As an avid editor myself, though: keep it up!