What do i use

[WILDBULL]

After I sctrach the letters or picture into a horn what do I rub on it to make the letters stand out

[Leathermonger]

Wild Bull, I use waterproof India ink that can be bought at Michaels, Hobby lobby, or any stationary store, I then use a toothpick dipped in the ink like a pen and write over the lines to fill, after its near dry, use some spit on a rag to clean off the surface, thers some enzyme in saliva that cuts the ink, them you'll need to sand off the ridges from cutting the lines with some 320 or 400, then buff with #0000 steel wool, hope this helps, LM

[Oregon Horner]

I personaly use india ink.  I have talked to horners who use a sharpie to darken the engraving.

Scott