I save the cranks, they are Ali.
Theres brass brake shoes in the rear wheel center & often the wheel rims are Ali too.



I use a angle grinder & cut thru the spokes, wear safety gear here as the spokes start to jump around due to the grinder & tension on the spokes.
Sometimes the spoke ends are brass too.

Not a lot of metal, but it all adds up.

I'm making a bicycle tow trailer from old bike wheels at the moment, I will keep you informed.