I have had Sonic Cleaners in the Workshop since Chicago,1966.They can do a'Too Gooda'job sometimes,Guns(& Rifles) that have 'Fine Engraving'and have spent years in tropical'Climes'build up rust in the engraving, and when'Sonic-serviced'the pitting destroys the engraving pattern. I had a Nimschke Engraved Winchester in the shop Years Ago from The Late Tommy Haas ( With letter of Originality from Historian R.L.Wilson)....After I had it Cooking in the Sonic for a period, then removed it, washed it off...Nobody was Happy with the results!! Barry's Method is what I basically follow today. Im sure every Gunsmith has their own Formula'for the solution.I have a Cold Heineken Formula, goes down well with all the 'Fumes'..We need more Humor in the 'Workshop'!!!Xchisles.