In December 2007, I realized that, once the tag is removed from an article that I've cleaned up, there's no evidence left of the work done. This bothered me, because I think that this kind of cleanup work is one of the most important things a Wikipedia editor can do, especially as we are leveling off in terms of total numbers of articles. If someone is working on Featured Articles, there is a wonderful icon to commemorate their work, but with cleanup, not only is there nothing like an icon, the only evidence that the article ever needed cleaning up is wiped out when the cleanup tag is removed! Depressing, if you want to be able to remember where those long hours on Wikipedia went to. So I decided I wanted a record of my labors, if only to make me feel like I've accomplished something.
My original goal was to clean up—to the point where the cleanup tag is no longer needed—one article every month. As of July 1, 2009, I'm challenging myself to do an average of two cleanups a month. And as of September, 2009, I'm now dividing my cleanups into two categories: General and Lead Only. User:TonyTheTiger focused some much-needed attention on lead sections that are not written as well as they should have. So I am going to add these to my workload, whether I find them here, or they are recommended to me.
Some of the links below will show only a relatively minor change, maybe even a change that will not be immediately noticeable. That doesn't mean that I just removed the tag; diffs will show significant improvements in each article.
One important thing I want anyone reading this to realize: Judging from the way that the listings at Category:Cleanup by month are regularly reduced, there are others who are doing a lot more of this work than I am. I wish there was a way of tracking these editors so that I could provide them with the recognition they deserve. I was lucky to have someone notice this work, but like I said, I'm not one of the major players in cleanup. If one of the articles you edit regularly has had a cleanup tag for a long time, and you notice one day that that article has been practically rewritten into a much better article, check the history to find out who's responsible, and make sure you drop in on their talk page to thank them. Even better still, clean up that page yourself. Happy editing!