I am assuming that pre MIM era color casehardened parts, such as hammers and triggers, cannot have the original color casehardened appearance restored once they have been refinished.

Put another way, if I spend X hours polishing such parts (which have been parkerized) I'm assuming the best result I could achieve would be 'in the white' parts which would not show color casehardening.

Comments are invited--particularly from anyone who's ever tried this.

Yes , they can be done. The secret to brilliant colors is in the 'mix' that you use. The parts are placed in a natural 'carbon mix' of charcoal , bone , leather scraps and other stuff , and heated to whats called 'critical tempeture. The process is mainly to add hard carbon to the surface of relatively low carbon steel to add wear resistance. The steel is heated till the pores open and absorb the carbon. The colors are a side effect.

It can be done with the right stuff at home. Try GOOGLE for color case hardening.

Doug Turnbull specializes in Colt and Winchester restorations. He is widely recognized as doing some of the best color work.

Firearm finishing services - color case hardening, gun bluing services, rust bluing services, charcoal bluing services from Turnbull Mfg. Co.

Once color case hardening colors are polished off, they're gone forever.
The only way to restore them is to have the part totally re-done in new color casing.

This isn't easy and you can run into problems like warping of parts.
Only a few higher end professionals have the process down to the point where they can do brilliant casing.
The best is, as above, the Doug Turnbull company.
They've researched the process to the point that they can do color casing as used by specific companies.

I just had two Colt Single Action Army Revolvers re blued and re color case colored by The Colt Factory and I must say that if you have a Colt in need of refinishing, I have not seen better case colors anywhere! The work coming out of the Colt refinishing Department now day is nothing short of SPECTACULAR!!! Their prices are very very fair as well.

Chief38

[QUOTE=dfariswheel;136018839]Once color case hardening colors are polished off, they're gone forever...QUOTE]

Thanks for confirming what I suspected.

I appreciate the other responses, but I'm not interested in fooling around with chemical processes or investing any money other than the cost of a sheet of emery paper.