wash it with wash n wax, making sure all soil n muck is removed from arches/underneath as it collects moisture and makes rust/rot. polish it. leave handbrake off. on a dry sunny day open windows n doors etc to let air in there.
mine stood for like a year and there was mould everywhere, on the wheel, gearstick, carpets e.t.c manky stuff to clean off :/
polish is waxno good polishing it if you dont wax it!for exterior i would give it a good coating of wax (at least 4 coats) then leave the last coating on and cover it with a cover, raise it up on axle stands if you can and remove wheels and stack them like suggested. If you can't, chock the wheels and leave the handbrake off! can guarantee the drums will stick if you leave the handbrake on! if you dont rotate the wheels you will need new tyres though.