Once the carbon pads wear off on the rubber keypads, they are pretty much finished. You can try to clean the pads, but you are likely just removing more conductive pad in the process. Yo can purchase a two part carbon paint kit from electronics part supply stores, and reapply the conductive portion to the pads. The unfortunate thing is once the package it opened, it doesn't last long and must be used shortly. Back in the day we used to line up a bunch of remotes that needed the keypads reconditioned and did them all at once to get our money's worth of the product. It used to be about $60 for the kit. You also may be able to purchase a replacement rubber keypad from the manufacturer. Best of luck.
