This post will show you a range of ways to detect and remove unused css from your site.
removing unused css will help your stylesheets load faster which, in turn will help your site load faster.
there are several ways to do this.
one way is to use a firefox extension : dust me selectors it can take a sitemap.xml and can scan your entire site. it will show you all the unused css from your stylesheet.
there are other ways:
unused-css.com will take your url and will scan it and will output the css file with the unused css already removed! – by default it only scans the homepage, but if you provide it with an email address then it will scan your entire site and will mail you the results and the clean css file!
gtmetrix.com have a cool little tool that will analyse a single page at a time using ySlow! and google pagespeed.
google pagespeed online is very good and analyses a lot of other things that can slow down your site, but the css part is very useful. it shows you slow css rules, etc