If you're looking for a way to mark explosions or fire - and if you're no good at the "cotton ball thing" - Gale Force Nine has a product that might appeal to you.
The Fire & Explosion Markers pack contains parts for three fire-or-explosion markers.
There are no directions, but how hard can it be to assemble three plastic pieces?
The resulting doodad is surprisingly cool when viewed at most angles, is durable, and can be taken apart for flat storage.
The marker works in multiple scales...
...although in 6mm, it is a much bigger explosion...