Rated 5 out of 5 stars
All those other cache clearing add-ons at best have a negligible effect - this considerably reduces cache immediately.
It's especially helpful if a window with many tabs is always open. I use Google Books as reference, which consumes a huge amount of memory (over 1.6GB). When my referencing is finished for the day I hit Clear Caches and around 45% of memory is reclaimed - I can then slum it on the web with a smooth-functioning browser.
Tools > Clear Caches