I remember Abe Chaber doing the sonic tank job on the locks n action of a rather nice belgian sle I have,which I bought after he checked it out & gave me the thumbs up.
Then he gave it the sonic vibe bath...sounds sexy...?
It was amazing how much lovely faded colour came up..even the grey/silver looked so really clean, not polished looking
well worth a try, imho
cheers
Franc
Any pics ?, I love nice belgian engraving