Help with bases/stands

Im new here, but ive been checking out alot of things on here and everybodies buildings miniatures look amazing, i was wondering if anybody had any ideas or tricks for painting burning ground or scattered cinders on a base, thats the idea that i have for when im done painting my warband, kinda make it look like their in an area of mordheim thats still burning. any ideas would be great thanks.

Cinder is rather easy: use fine sand, paint it deep black and highlight it twice to medium-dark grey.
Burning pieces are mistery for me. Once I've seen fire made of celophan (this silver to pack sandwiches) formed in irregular shapes and painted reds and yellow with cotton made smoke painted black. But I suppose it is good for bigger stuff like buildings, not bases :/

uh ... haven't tried it myself, but I would think for burning ground you could smear some putty or filler or whatever and then do the opposite of highlighting.
I would start with a clear bright yellow, and then work my way up through orange, to red, to black.
You should get some ideas if you google on miniature lava bases. I've seen them around.

cheers