Firefox is the best when it comes to browsing experience and killing Internet ads using the AdBlock Plus add-on, but it’s a complete and utter piece of shit when it comes to memory. Here’s how to clear the cache directly:
Another part of Firefox 28.0 in Tools / Options is
Options>Advanced>Cached Web Content
If I find an add-on that I can easily use to do the same thing, I will EDIT this post.
John V. Karavitis