You can get a flat black finish on your clip using etchtant and BC gun blue.
First , grab some 320-400 and scratch the clip up real good , all lines same direction of course.
Wash with soap and hot water , dry.
Grab some q tips and your chemicals , put a nice coat of the acid etch on it and let it work in, if it pools up reapply it in the areas it's not pooled ,you want it to 'burn' deep as possible.
Let sit maybe ten minutes then rinse , nuetralize, rinse , dry.
Start over with another app of etchtant , but just one coat , then after a minute or so , generously dab on your gun blue , you may have to paint it on with the q tip , make sure it is as uniform as possible , let this mixture soak in good.
Put a fan on ( beforehand ) so you don't sniff the fumes and be careful with your chemicals , don't want to ruin your day.
After a few minutes , rinse and nuetralize , dry off.
You'll see splotches of dark most likely , gently polish with extra fine steel wool and then coat in CLP or similiar and let it cure overnight.
You'll end up with a flat black clip , it's not going to look picture perfect but it does work , it will wear off over time as well.
I've used this same method on stainless blades as well.