Drink it!! (That is of course a joke). I'm not sure about burning it either to be honest, could be dangerous. Nitromethane's pretty explosive stuff in the right quantity and with a little compression.
If you do burn it, for gawd's sake be very careful! Not near property, wear clothes you can remove very quickly if necessary, have an extinguisher handy, etc, etc.
The most socially responsible thing to do would be to recycle it, as suggested. Mother earth will thank you.
