If it is disintegrating... then you'd have to change a new piece.
Common problem for those who have sweaty palm. My suggestion is to gaffer the camera after changing a new rubber piece.
Actually, it could be costly, I don't really agree that it is cheap!
Not sure for CSC, but for NSC eg. for pro bodies like D2/D3/D4, the CF door rubber is ~$25-$40 to change, the front piece ~$60, side grip another ~$60-$80, bottom piece ~$40 and so forth. My experience once I wanted to 're-cond' one of my bodies, I paid ~$240 to change the whole camera rubber.
Personally I really don't recommend to change just 1 single piece cos after changing a new piece on one side, another part of the camera starts to peel. So it ended up every piece has its own 'lifespan' and normally they are ard the same time! Thus ended up many unnecessary trips to the service center.
I rather change all pieces once and for all, then think of a long term solution to protect them and make them last. Gaffering is a good option, but remember to change the gaffer tapes once every 6mth or so cos it all depends on how often you use the camera.