Dewalt Grinder breakdown

So I have spent hours searching & reading past threads and can't find what I'm looking for. I would appreciate your help.

My boss has a lot of old dewalt grinders and chop saws Non-working some in parts & pieces. I need to dispose of these and don't want to pay to haul them off. I thought breaking them down would be the best way to go.
I've done 1. I took out the motor, cut off the cord separated the plastic pieces but I have no clue what the head of the grinder is made of. A magnet does not stick. I search the mfg site but they do not list what it's made of. Since most of you have a grinder I thought someone might know.
Is it trash or what pile should it go in? or am I just wasting my time altogether?

Thanx in advance

its cast aluminum