Never heard of this before, very interesting!My grips have been sticky for years but I haven’t bothered to fix it.
Not a brag by any means but in 2012 I owned a Ferrari 348. Bought when they were at their absolute cheapest. They as well as some of the later models are notorious for getting sticky switches throughout them. Of course all of the items were a rubber coated type switch or cover. There are dedicated services that will remove the stickiness. I would venture to think it is some sort of urethane that eventually breaks down. The stickiness is very similar to uncured urethane. It would make sense that alcohol would work since that effectively cuts urethane. Acetone may do the same thing but you would have to be very careful with it.