Brass Pulley for My TT


I recently had a machine shop make a Brass pulley for me to try, it is working great but; I am seeing some yellowish dust which I assume is brass. Is this normal? I don't have much knowledge of Brass so I am looking for answers??? Will this stop after a while or not? The belt is made of Mylar.. I have cleaned it off a couple times but it is still producing it...
jsman
Cymbals are made of brass, as are saxes, etc. Brass oxidizes, which is why cymbals become tarnished. Not a good material for a pulley, imo. You could have it chrome plated, I suppose.
I would hazard a guess that the friction of mylar belt is polishing the brass, therefore, leaving a slight residue.  This is not a bad sign as the smoother the brass surface becomes, the better molecular adhesion. 
brf,
I am hoping you are right, that's what I am thinking also. That the shop didn't polish it enough I guess time will tell.