Disabling the GMail spam filter and handling it yourself using SpamAssassin

I've been using GMail ever since they decided to allow users to download their mail using POP. I was happy reading my email as usual in mutt. The only problem was that I had to log onto the website once in a while to clear out my spam folder and fish out the false positives.

However, as the amount of spam I receive daily started growing exponentially (in part thanks to my involvement in Debian), I became more and more dissatisfied with this solution. I had to login several times a day just to keep the levels of spam down to a manageable level. I tried emailing the GMail support team a few times without success.