heating ammonium/sodium persulphate

[smokyLED]

what is the best way to heat up used ammonium persulphate? i store it inside a plastic bottle after using it, and i don't want to put it in the microwave.

[gogo2520]

I use a aquarium heater.
      My tank is a simple tupperware cantainer I picked up at ST. Vinnys for a buck. Then I stoped off at  Wallmart and bought a air pump and one of thoses long air stones and a heater. The heater cost the most, I think it was around 15 bucks.
      It takes the heater about one hour to heat the tank  (my holds a gal.) to around 105 degs F. Been using it for over a year .
                                        gogo