Hi there.
Firstly, 10 years isn't old for a Corn. 15 years is the average lifespan in captivity these days. He should be in the prime of his life.
And three mice in one sitting! Phew, that's a meal and a half for any Corn. One adult mouse every 10-14 days is the standard regime, as Tula mentioned. How often are you feeding?
Shedding more than usual, does indicate a health problem of some sort. The tip of the tail discolouring is probably the end of a retained shed. If left untreated this could cause him to lose the tip of his tail and in an extreme case, might lead to blood poisoning and death if not dealt with. The shedding could be related to this.
I wouldn't muck about with damp hides trying to deal with it. Go with your gut - if you think something is seriously wrong, then it most probably is. Get your fella to a reptile vet as soon as possible.