You really want to do it? Spill brake fluid on the hood to remove the paint.
Then pee/puke/****/fap what ever you want to do on the hood.
Then burn the car.
People come here to ask how to repair a paint chip on the hood so the rust doesnt form and you are asking to rust the whole hood. lol.
Man, I need to sell my car. The day I actually see an e46 with a rusted hood, I'm going to put in on sale.
Want to buy it OP? I have a couple of paint chips on the hood, that will help you in rusting the hood sooner.