Homemade recipe to do exactly this, and do it well (many say better than this powder or whatnot you are looking for...)
Ingredients:
Several lengths of copper tubing (1" in diameter and about 1' long work just fine.)
Several lengths of any variety of garden hose.
One drill.
Process:
Drill about a dozen holes randomly in the copper pipes. 1/8th to 1/4 inch width is fine for hole size. About what fotze would slide into easily....
Put a length of garden hose into each section of pipe.
Throw pipe into fire. Effect lasts for quite some time depending on size of pipe and composition of hose. Estimated 30 to 60 minutes per pipe.
When fire is cool in the morning, pipes can be "reclaimed". Just need to insert new section of hose.
Warning.... do not attempt to take out pipe after it has been sitting in the fire for a while. Yes, it is hot. Yes, this is like the McDonalds coffee warning. And yes, I actually do expect someone to try such a silly idea!