hey Bilbo,
without using paint...start with beating the snot out of them whips, chains, hammers, grinders, nail guns...whatever floats your boat down that avenue.
From there find yourself a mudpuddle or make one for that matter and smear on some thick and heavy mud and let it set to dry.
Once it's dry break off some of the bigger chunks and leave the rest. Then get some gloves and find a bunch of grass clippings and some ashes and rub, rub, rub...hopefully this will give you enough old age for this year.
Once the holiday is over leave those suckers outside for the real aging process to get going....Hope this helps...