What is the best way to clear Plone's CSS cache?

I am using Plone and CacheFu behind an Apache caching reverse proxy. Plone combines multiple CSS files into one file such as name-of-css-file-cachekey1234.css where 1234 is a random number, and it may take an hour for CSS changes made on the filesystem to show up on the site. How can I see those changes sooner without slowing down my site by enabling CSS debug mode?

From stackoverflow

• In the ZMI, if you visit portal_css (CSS Registry) and hit Save without changing any options, then a new cachekey#### appears and the new CSS rules show up on the site.

• Click the Save button in portal_css, and you will get a new CSS file.

  That's exactly why that feature exists, so that you can cache aggressively, and still get an updated CSS file when you need it.