If you happen to be in possession of spare Car Parts for New and Used Cars and, for some reason, you don't need them yourself, then there are a variety of strategies by means of which you might go about disposing of them.
To begin with, you could sell them for scrap. This is really only a good option if you suspect the parts are no longer functional. A good, eco-friendly scrap dealer will ensure that the metal is reused in an efficient, environmentally-sound way.
However, if the spare parts are all in good condition and will continue to function effectively, then you will almost certainly be able to get more money for them if you sell them to either an auto-repair shop or to someone with a car for which the parts were designed.
Alternatively, you could also donate the parts to a charity. There are a variety of organisations that will relieve you of your automotive spares. These are then sent to needy communities in which people can't afford to repair their vehicles, or they might be sold on in such a way that the proceeds go to a specific cause.
In short, there are many options open to you if you are keen to get rid of your vehicle's spare parts. You could scrap them, sell them or donate them to a worthy cause.