I do something similar. 1st- Never use something that will be used for food again. There are 15€ used microwaves listed in my local secondhand app, but I live in a small apartment, and I don't have the spare space.
2nd. - I don't do this stuff in the kitchen.
I have a small induction plate, which can actually be set to temperature or power level, and wich is surprisingly accurate! I spent a morning doing testing, and the damn thing would be within 5°C everytime.
I use an enameled pan, which has been retired from food use, and do this in the balcony. I shake it around every so often, with the temp set at 110°C.
It really irks me how a bunch of Youtubers ignore basic safety measures, like using your oven, microwave etc to dry silica, filament, anneal parts etc. We normally have no clue as to the modifiers, additives, etc, or even the actual effects of fumes of the base plastics (maybe there is research, but I haven't seen anybody looking for it)
I'm working on a cheapo enclosure, and already have designed and printed a cheap and cheerful filter, to use EVERY time I print, no matter what the filament. If I don't have hard data about the toxicity of a material heated in my breathing space, I'm going to treat it as toxic.
Safe by default.
Great advice! Use two food preparation appliances to heat a material you have no clue about what it offgases in addition to water.
Enjoy your food.