Yeah, I buy the pyrex 8 cup (2 liter) glass measuring cups with the plastic lid on them. It is important to keep it covered in the microwave to minimize any splashing and also keep the evaporative water loss to a minimum. Even with that, you may have to add a little distilled water occasionally if you start noticing crystals of k-ox on the bottom of the storage container. In my microwave, 1.5 liters of k-ox will go from room temperature to 140 degrees in six minutes. I then zap it with 1-1/2 minute bursts after each development to keep the temperature at about that level. For really warm prints, try it at 145 to 155 degrees. You can get some good results with even hotter temps, but you start flirting with the possibility of breaking down the sizing of the paper and getting some strange unwanted results. Some papers seem more robust than others. I find that platinotype (yuchhh!) and stonehenge start to break down at 150 degrees or so. Platine and Cot seem to be able to stand hotter temperatures. Whatman's is pretty robust as well. As always, YMMV.