bought a trash compactor at a Habitat For Humanity ReStore, and it came with out a knob, so i made one up real quick.
this fit a bit tight with my printer, but it works flawlessly in the compactor.
you may have to fudge the dimensions a bit, or do some post-processing to get it to work.

it does need supports to print this.
i printed it with the knob face down, and supports for the overhangs.