I have a few handguns with different finishes on them.......
On my bright finished guns I use Flitz to polish up the finish....
I was wondering..... What do you guys use on a non-bright finished gun....?  Say a glock or regular sig with a standard black finish...for example.....  Could you use the flitz on that too?  ANything better?
Thanks

tim

ALL metal polishes are abrasive.  The only difference is, some are less abrasive than others.

ALL metal polishes will, faster or slower, abrade the finish and thin it, until the finish is removed.

Bottom line: DON'T use metal polishes on guns with a surface coat of any type.  
The proper treatment for a blued or coated gun is to gently wipe off with a clean cloth or patch with just a little lube on it.

One of the bests rust preventing lubes for this is CLP Breakfree.  
Be SURE to absolutely shake the DICKENS out of the bottle or can.  CLP settles badly and has to be WELL shaken to mix the components.

Metal polishes are OK on stainless, but will quickly alter the original satin finish to a bright, shiny finish.
Never use metal polishes on the areas that are bead blasted, it'll ruin the matte finish in those areas.