I was shooting my my newly acquired S&W, and afterwards noticed some burned on residue on the outside of the stainless cylinder. I tried to use some break free powderblast spray but that did not seem to dissolve it. I finally tried a scotchbrite pad which cleaned it but left tiny scratches. Not wanting to damage the metal any more is there any solvent that would dissolve this burnt powder, without marring the stainless metal?