I drilled holes in the bottom of this can and filled it with rice hulls. Then I turned on an exhaust fan installed in a window and opened a window near my kitchen. I put the can on a stove burner. The gases that escaped from the bottom of the can fed the flame of the stove burner, turning it yellow. Although it didn't smoke, because the burner flame burned the smoke, it did stink and set off smoke alarms. I had to grab the can with tongs and shake it to redistribute the hulls because the hulls near the top didn't get hot enough.
I am going to experiment using this as a substitute for perlite in mixes with peat moss. First, using tomato seeds.