My experience in taking them apart is that you shine the copper contacts with scotch-brite, sometimes flop the copper contacts end for end, and they work fine. Taking them apart, just use your pocket knife to gently edge the plastic slots and dots over the moulded raised spots in the switch body. I put in the bottom with the copper rockers and such, then turn it upside down and balance the two balls on the springs while inserting it straight up. Once in a while I got to redo it to get it right, but all the switches work on my five bricks.
Switches from pick-your-junk are about 5 bucks and still may need the treatment, dealer is 5 to 6 times that.