Dualshock 3 Issues(Random Buttons Being Registered)

I've had my ps3 for quite some time. I would say about 2 years. It's a slim mdoel 120gb. It came with a black controller. It worked the way it is supposed to for awhile but then after maybe a year; random button presses were being registered. it wasn't that bad though. I eventually just bought another one(white) which works fine. I still use the black one occasionally but it seems to be getting worse. I noticed that when I press in the left analog stick, that's what is making it act up. Or if I kind of squeeze it. Very recently, I noticed my new controller is starting to do the same. Is there something I can do to either fix the old or prevent the new one from going down the same path?

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