Mollebneum coating on compression nut?

[SMITHN8R]

Mollebneum coating on compression nut? Hey folks, would appreciate any info you have to give, advice, opinion etc. All welcome. I am building a rotating racking arm for my plastic conical. I have all my parts, but when I received my 3/4" stainless compression nut, it has a gray coating on it. I think this is a molly coat for high pressure situation but not sure. It seems like some have it and some don't, but the guy at McMaster Carr said that's all he has. My questions are, what is it? Will it leech into my beer? How do I get it off? My goal was to go all stainless with the racking arm, but then I ran into this. Any input is appreciated!

 

[Ben58]

Not sure about that nut in particular, but I know the Parker compression nuts have an Inconel coating on them, same as an immersion water heater element, which is safe.

 

[jpc]

Try searching the web for "molybdenum"... From a simple search, I see that it's used in some stainless steel formulations, but I don't have the time to dig deeper.

 

[acidrain]

Test it with a magnet. If it's truly stainless, it should not be magnetic.
If it is stainless, maybe it will polish up.