If it's dark brood wax, it helps to filter it several times. Cindy Bee did a presentation at Young Harris, putting the old brood comb and some old comb ruined by SHB into a flannel pillow case and putting that into a Turkey Fryer of boiling water. She then filtered the wax out so that the yuck was left in the pillow case (has to be all cotton, preferably old flannel).
I did that with some old brood comb and old ruined by SHB honeycomb. After I got the brown wax disc out of the huge pot I had originally filtered it in, I then broke the disk up and put it in my solar wax melter. After the solar wax filtering (through a paper towel), the resulting wax was canary yellow and gorgeous....didn't have the honey smell of cappings wax but the color was amazing.
Linda T in Atlanta