Green Brass/Slip Joint Plea for Help!

[Hamp]

I drove out to visit my brother for the first time in a while. Of course we started playing “show & tell”. He pulled out a knife roll full of Case/ Boker etc. slip joints that apparently haven’t seen the light of day in a while. Several of the brass bolsters have turned green & nasty. I went over them with Brasso & a Tuf Cloth but the “green” is showing through the translucent yellow scales on one of the Case knives. Anybody have any advice on cleaning these &/or preventing it in the future?
Thanks!
Hamp

 

[Quiet Storm]

I dunno what else you could do to restore the original color (apart from polishing the brass), but to prevent this from happening again you'll need to keep those slipjoints away from leather.