in a warm dry place where they won't change temperature much. preferably not in a garage.
I'd suggest that once in a while we should throw our grips in washing machine, they come out like new with enough moisture and extremely good grip.
would the bat fit in the washing machine tho?actually when i stick my goalie gloves in the washine machine it seems to activate the latex quite well and makes them very grippy, so can see this would work