For the first time I agree 100% with TM7. Skip the frustration, buy a new key board.
Last spring my son left one of those energy drinks in the S-10 over night. When the temp went below freezing it exploded, spraying sugery syrup everywhere. Everything cleaned up OK except the radio. He worked and worked on that radio. He never was able to get it to work right, buttons still stick. I finally last week stopped at the salvage yard and bought a replacement radio out of an S-10 Blazer. Since it is still a stock Chevy radio, and I changed and kept the unaffected worn volumne button and face plate, he thinks Dad did wonders cleaning it up. Let him think that.