I use Trans-Tint dye. It is available at numerous places online. I buy from Woodcraft. You get a little bottle for just under $20, but it will be enough for years of use unless you build a lot of dyed calls. They have a fair selection of colors. I mix the dye with denatured alcohol and prefer to dip my pots as opposed to rubbing the dye on. The color will absorb more into end grain than it does in face grain. It also will highlight any sanding scratches, so be sure to sand to at least 400 grit and remove all scratches. I like to do about 4 coats minimum for good color consistency. The color will darken a bit with each successive coat.
