Do you take the batteries out from computers motherboard that you have on the shelf?
I do, because I found some old macintosh where the batterie acid destroyed the metal conectors on the motherboard..
All Lead Acid, Alkaline, NiCad, and NiMh type batteries should be removed from any equipment, prior to storage.
Removal of Lithium type batteries, in MHO is optional. I've never seen one leak. Plus side to removal, the batteries may still work when you put them back in. Down side to removal, loss of system clock and settings.
My advice: take'em out.
If you've got one of those "barrel shapped" batteries (many old PCs and Amigas had them): definitately take'em out. They will leak and burn right through the motherboard and kill your machine.
Many will survive longer if kept cool (in your fridge), but check wikipedia for definite values (ex: Lithium Ion ones like to be kept at 40% charge and cool)