I found out by complete accident a few years ago that a couple of pieces of kitchen paper dropped in the maggot box will dry them up a treat if they get a bit sweaty.
For cleaning or storing I use lightly dampened sawdust as it helps to keep them hydrated and plump. Weetabix is an old dodge I had forgotten about and many a breakfast cereal has been slipped into a coat pocket from fishing hotels up and down the country.
Porridge oats, as well as drying them off, also acts as a skin conditioner and they always seem to feel softer, like a wet chamois leather or a tench, when they have been stored in oats.
We used to get the blows on a sheep's heart then move them into a biscuit tin and feed them on milk soaked oats when I was a youngster, the maggots bred that way were fantastic big beasts and creamy white with huge food spots.