You are the first person who has ever wanted to cause rust to a car, what is your problem ?
Battery acid. Beware, though, because that stuff will give you serious chemical burns if you get it on your skin or in your eyes!
Need to cut through the paint down to metal. 40 grit sandpaper will do this. Once metal is exposed, the moisture in the air will slowly eat away and before long, there will be rust forming, paint falling off... Also, sprinkle some salt on it after you sand it, or spray with salt water.
Don't have to sand the paint off, just rough it up a bit so you can see a little metal.
That makes no sense. Why are you trying to rust a car?
Keep it in Muddy Water
So we have this old motorless 2002 Toyota Camrey and were trying to find a liquid that we can spray it with to make it rust which water won't really work with. Will draino work or something else that can be store bought that isnt a spray? We're filling up squirters with liquid and trying to rust the car