Casting Aluminum question

OK, so there has been a lot of talk around here, about casting aluminum for
VW heads. It was here that I first learned that you can not use iron
crucibles for melting aluminum.

So, what if you need to cast a little job for something that does not to be
a pure aluminum part, for a non-aircraft application, where strength is not
very important? Would it be good enough?

My part is a socket (retainer) to go on top of a tractor shift lever. Think
like a donut, with the inside of the hole shaped like would be formed around
the outside of a sphere, or half of it. It has a retainer that screws down
around the outside of the part, holding the shift lever and ball around it,
down onto the transmission.

I believe the metal part that needs to be replaced is/was made out of what
is usually called "pot metal." What the heck is that, anyway?

So, what do you all think? Contamination from a cast iron crucible OK for
this part?
--
Jim in NC