if you run brood comb through a solar wax melter a number of times, and continue to filter it, there will be no particles or impurities left in it, unless you have treated your bees with something. (not sure how much residue remains). but you can use it for candles. i don't, but do know someone who does, and often times she will color and add scent to the wax. i use this wax as pete said, to add wax to foundation.