This may qualify for stupid question of the week, but does anyone know how to tell if a part is cast from aluminum or pot metal How about aluminum vs. stainless stamped parts?

I only ask because I spent about 2 hours this morning polishing a cast gauge cluster (for my van) that I originally thought was aluminum.

It came out okay but didn't polish-up as easy as I thought it would. I started thinking about it and couldn't think of any good reason why mopar would have cast it from anything other than tramp metals.

For a long time I was never sure if the early grille I added o my van was aluminum or stainless since it seemed so stiff, but saw a similar grille that had been anodized in an old van magazine.

I always figured (incorrectly) that a magnet would stick to potmetal
until trying it this morning on the vans door handles.