Green corrosion on BMW exhaust pipe

My client serie 7 2011 bmw 's exhaust pipe have some green corrison on the lip.. all 3 other pipes is more the usual black colored lip from exhaust gases.

I tried by hand some metal polish and it removed a bit of the black. like 15%..I did it by hand. I'm thinking next time bringing my ball + drill with metal polish should work a bit better.

I was also thinking steel wool 0000 + metal polish. umm heavy cutting compound + metal polish? how about 1000 wetsand + steel wool + metal polish?

When I come back, I want to have as many option as possible to be able to fix it.. I mean.. at the end.. it's only a 1 year old car, I'm surprise just a metal polish by hand didn't fixt most if not all of it.

 

I have seen this on a couple of my customers' new 7 series as well. My one customer actually contacted the dealer when we first noticed it because neither of us had really seen it before and he wanted to make sure there wasn't something wrong. They told him to not be concerned with it.

Some steel wool and a metal polish should do the trick, did for me.

 

Try 0000 steel wool with Optimum Metal polish.