francescolanza.com

In case there’s a need to clean up a css, removing empty lines and unnecessary backslashes, optimizing selectors and properties…and why not, decreasing the file size, here’s a quick tool.
If you style sheet is quite big I suggest to optimize small parts at a time and test that everything is working as expected ,just make sure you keep a backup copy of your files before editing, when things get nasty better be safe than sorry.

http://www.cleancss.com/