Ruger engraving & rust.

My LCP Custom and LC9s developed rust in the engraving but the rest of the gun bluing if fine. I tried a cold gun blue that states it works until you place oil on the area but it did not turn the rust blue. Since the rust is low into the metal it is not like working with surface rust. Have you guys have engraving rust and what did you do?

Try a extended soak of the part in Ed's Red or a 60/50 mix of ATF and Acetone in a sealed container for about a week .
Then toothbrush out the engraving.
Who know's ,,,,, might work.

Cold blue will not work over rust. Scrape out rust with a needle or sharp dental tool first, de-grease with alcohol and then touch up bluing.

Thanks for the feedback. I am going to dig out the rust and touch it up. I wonder how many Ruger owners are having the same thing?