In my experience (usually with old video game controllers and cheap touch tone telephone handsets), most contact-button problems are incredibly difficult to "repair", and any repairs you make end up malfunctioning eventually anyway. I remember the Atari 5200, its main A and B fire buttons were those rubber-contact things and they wore out fairly quickly. I tried conductive paint, foil, lots of cleaning, etc., and nothing worked well nor lasted any length of time. In the end the only repair that worked was to cut up and mod the controllers to use great big Radio Shack pushbuttons instead.

I guess what I'm saying is, good luck with your efforts, but don't be surprised if they don't result in anything.

I've got a Rio remote that's doing the same thing yours is doing. Luckily I had an extra on-hand, I'm not sure what I'm going to do when the extra one goes bad.