How can I fix my PS3 controller?

I repaired a PlayStation 2 controller whose circle button wasn't working reliably by taking it apart and cleaning it. All I did was use tissue to wipe away the grease and dirt that had built up on the pads and contacts. The direction pad should be easy to clean, make sure to clean the pads on the rubber part, the film covering the motherboard, and the contacts on the motherboard itself. The L1 trigger will be trickier, you'll probably need to consult a teardown to see how to get access to the parts that need to be cleaned.

Don't be aggressive, these parts will also wear out and when that happens there's little you can do to fix the problem. You want to do as little a possible to hurry this along, so be gentle.

I've also done the same thing to fix TV remotes whose contacts have gotten dirty, but I should note this problem usually only occurs for me with the commonly used buttons. Since the direction pad doesn't get a lot of use in most games, this may mean that you have encountered a different problem. Unfortunately that would also mean there's probably nothing you can do to fix it.