Do NOT peel off shed. Ever! it can hurt them. most times it will come off on its own. if there is leftover shed and it is stilll stuckon for several days, up mistings, warm showers, will help get the excess off.
If you pick any shed off the cham, then it may damage the new skin underneath and may even lead to infection. Best thing to help them is keep the humisity up whilst they are shedding, but give things (including the cham) time to dry out between mistings.