[Newton]

Have you tried alchol and a Q-tip? Any abraisive will remove the blasted finish, and you would need to have it blasted with glass again.

 

[Ledbetter]

Ever tried Kroil? Soak and rub with a rag.

 

[bad4u]

Since the gun has a non-blued finish, I'd suggest using a stain remover such as Tarnite, or any other tarnish remover which lists 'oxalic acid' in the ingredients.

Oxalic acid will digest oxides, without attacking the surrounding stainless steel. It's pretty much wipe-on, wipe-off simple.

This is oviously not suitable for blued guns.

 

[popeye]

Thank for replies. Will experiment this weekend.