There could be a few different effects determined by the color. I picked flour because it kind of replicates the dust kicked up by a shell hitting a building, but other things might work like ashes as you suggested. Fireplace ashes could work real well I would think. I got called away today (visitors from out of town - relatives)! The typical summer string of long lost relatives coming to the coast on vacation...that's what I get for living so close to the Pacific! I hope to get some more testing done today (its 1:30 am here).

When I get my paintball shooter there won't be any problem in kicking up some dust, but the little BB's are a challenge. But, I am encouraged, as the popping balloon does a good job kicking flour up into the air. I'll report in the early PM today if all goes well.