Worn game pads - fixable?

I've got a few game pads with worn buttons. The button press isn't very resonsive and you have to press it very hard for it to register. I'm going to take one of the worst ones apart and see if I can repair it. Has anyone done this before with any success?

Well, you could try cleaning it. BTW what system is the controller for?

Sounds like it is the membrain that is worn out inside and unless you have a replacement there is no way of really fixing them, I have fixed a Snes controller recently but I done that using parts from a broken controller, I also fixed an N64 analog stick by replacing the stick itself with one from a third party controller and it is actually a better stick. I also tend to stip the controllers and deep clean all the buttons and holes that they go in as some times all the crap they collect over the years causes them to jam up.

Sometimes you can fix worn-out buttons by putting little circles of aluminum foil under them. Sometimes it's just a bit of dirt that got in there.