The key is to find something that looks like it's about to dis-in-te-grate. If it seems like it will absolutely fall apart when you set a finger on it, you're on the right path. The older the better. The dirtier the merrier. Pick an idle object between a cactus growing in a brick, a wooden African chaise lounge (probably infested with termites) and an old radio that will never work. Jackpot if you can't even tell what it is.