I have for many years soaked dirty rusty receivers in a bath of the following with nothing but great results.

Prolix biodegradable gun cleaner
A bit of Hoppes #9
A bit of Liquid Wrench
And I thought I put a dash of Simple Green now and then.

I have soaked many old SXS" in this many times with no adverse effects.

My partner topped the bath off with a bit more Simple Green
the other day.
Receiver soaked for 3 days and today took it out and the nice color case hardened metal is now a dull gray in some spots.
Out of the tank it was similar to paint coming off after using stripper. Maybe a clear coat.
Any ideas what happened?
Is it possible to have a fake or painted on color case hardened con job finish.
Thanks for any ideas.


AIN'T MUCH A MAN CAN'T FIX
WITH SEVEN HUNDRED DOLLARS AND A THIRTY OUGHT SIX