I noticed lately (I just started playing a lot more after playing infrequently for many years) that one of my problems when playing is that my fingers slip off the keys! I feel like I need some chalk for my fingers like gymnasts use on their feet. Maybe my cheap piano's keys are too slippery. Any ideas to get a little more traction between my fingers and the keys? My Chopin ends up Chopunk

hmmmmmm.......

how about a chalk ball that climbers use? You can get one at any store (or climbing gym) that sells climbing equipment. They work really well for climbing, can't see why they wouldn't work with piano.