Find CSS not applied rules

Question

Hello,

I have a big CSS styles sheet, (about 6500 lines). Is there any way to determine which rules do NOT apply in a given page, (firefox plugin, a web util, or something) ?

Thanks!

PD: Using Firebug I can find which rules apply, but I can't find which rules don't apply.

Answer 1

Firefox, add extension Dust-Me Selectors. It does just that

Answer 2

In the FireFox add-on, Firebug, CSS rules which are overridden by other rules are crossed out.