When I was a kid and we had a 2600, when those things would start to go we'd carefully peel the sticky clear "tape" covering the PCB off and flex the switch/pad until it had a "hump" again, then carefully replace it, put the tape back, et volia.
I had a 2600 stick that lasted from ... '81? until '88, used it on my 2600, then my Vic-20, then the C64, then the 128 and finally my A500, where it finally died during a particularly intense game of Falcon
