Actually I think your right, it is ash.
Thanks! good to know that a well drawing flue will take care of it, as well as the smoke.
I have an old electric forge blower. I'm not sure what make, but it does have the name Hastings Foundry, (I think) on it . Interestingly that foundry used to be in a town about an hour from where I live. I have a fairly makeshift air gate to control the air.
I think sometimes the problem is to much air and not enough coal on the fire and so I get stuff flying out. I just have to be less stingy with my coal.