Scrap cars and trucks ar an absolute treasure trove of resellable goods. Lets break down the income streams from parts removed.
Catalytic converters: Did you know that catalytic converter contain Platinum? Yes they do and many companies process the platinum out and will pay you from $20.00 - $300.00 each for used catalytic converters depending on the size and type.
Usable cores: If you ever purchased a remanufactured starter, alternator, transmision, or engine from an auto parts store. Chances are it is on it's second life. Rebuilding companies will purchase scrap engine parts in order to use the oem castings for rebuild.
Resellable items: Headlight and tail light assemblies are very expensive to replace. Oem cost can be anywhere from $50.00 - $400.00 each.
A running usable engine can net you $300.00 or more.
Alloy wheels are another good seller.
Most of the time when car, motorcycle, marine ect batteries die, it is because of sulfation. This is a build up of corrosion on the lead plates inside the battery. There are proven processes available to remove this and restore the battery to almost 100%. Batteries are expensive and people will pay for restored batteries.
Here is a very well written guide to battery restoration.
All of these items can be resold locally or over the internet for tremendous profit.
What remains of the car the shell is a 2000 - 3000lb hunk of scrap steel. Upon the writing of this article steel is curently at about $250.00 per ton. SEE STEEL AND COPPER RECYCLING
The plastic internal components can be recycled for there current value SEE PLASTIC RECYCLING
In some instances the seats and opholstery may be resold but as a general rule they will be scrap. If you strip apart or shred the seats the steel can be easily removed for recycling and the rest landfilled ( currently I know of no way to recycle this material).
The wiring harness can be recycled SEE ELECTRIC WIRE RECYCLING
A skilled dismantler can easily deconstruct a car in one day or less. I personaly know two individuals that do this part time (one day a week) and make over $1500.00 per month extra income. Much more money can be made doing this full time, however in many states you have to obtain a salvage permit if it's your primary source of income.