I've also been looking for a durable repair technique for remote control button conductive contacts. I'm trying to fix intermittent buttons on my URC MX-700. I tried doing disassembly and cleaning with no improvement.
Have you run across this
option? It consists of new conductive pads to replace the worn pads on the bottom of the buttons. There is a video there showing how to use wire cutters to snip off the worn pad and then use silicone glue to secure a new pad in its place.
I ordered a kit on ebay for about $8.50 total. I'll give it a try and report back if there is interest.