Afff is a very good idea as with alot of the new metals that are going into the blocks in cars will react with violently to anything else it is also a very easy clean up. Afff is also cheap you can make your oen with some dawn dish soap and get the same effect as long as you can airate the foam. All the foam does is take one of the key ingredients out of the fire tetrahedron. I hope this helps some what.