If you are doing cars,witch by the way are great to do you need to take as much as you can off the car the cat,radiator ,the wheels,alternator,starter,motor and trans,some engines are aluminum heads and go as irony, trans are always irony,don't forget the battery,also some have aluminum hoods and doors,when I used to do cars I brought the shell of the car to the shred,every thing else was separated and sold for their true value,that's how you make the money.