I read on here that fireplace ash is good to add to "homemade" dust bath bins. What about the ash that collects in the can under a charcoal grill? I've saved a large bag of it, and it looks nice and clean (no food debris in it) but I'm wondering if the ash is contaminated with lighter fluid or something in the charcoal we used (or does all that burn off?) My house doesn't have a fireplace so this ash is the best I can come up with. Thanks for any advice!