Automatically remove un-used CSS classes from a project

Question

I'd like to compare my CSS files with the classes that I'm actually using in the site, and generate a new CSS file that contains only those classes. The point being to get rid of classes that I'm not using.

I previously used the Dust Me Selectors extension for FireFox to find the used and unused CSS selectors but it doesn't work in FireFox 6 any more.

Are there any alternatives?

Answer 1

When you put your site to GT-Metrix. Than you can see the un-used CSS selectors. Or you can do it with Google pagespeed.