How can I effectively clean up styles in a large web site?

Question

Our web site has been under a constant development for a better part of the last five years. As it happens, pretty much all the styles for the site are in one big CSS file.

Answer 1

Additionally, there are many sites that will search for these for you. Like this one: http://unused-css.com/ I don't know how they measure up to Dust-Me Selectors, but I know that Dust-Me selectors isn't compatible with Firefox 8.0.