Blackened microwave: windfall or demon core?

September 20, 2010 12:37 AM

Is a blackened microwave dangerous?

I scavenged a free microwave from an electronics recycling program, but about 10% of its innards are scarred with black char marks.

I figure someone once microwaved a fork or something, and the machine is perfectly fine. The inamorata wonders if the marks could indicate a danger of fire or food pollution.

Who's right? -- is there any reason to imagine this microwave could be dangerous to use?

posted by foursentences to Technology (8 answers total)

Best answer: Microwaves are cheap. Don't waste your time with uncertainty and lingering doubt.
posted by ZaneJ. at 1:30 AM on September 20, 2010 [1 favorite]

Best answer: Or somebody was experimenting and it's full of all kinds of nasty, toxic burned-plastic residues. What ZaneJ. said.
posted by musicinmybrain at 6:11 AM on September 20, 2010

Yep. And also gross. What are you nuking? Food or weirdness?
posted by evil_esto at 7:11 AM on September 20, 2010

You don't know what it was used for - don't use it for food. It's fine if you want to use it for melting beeswax or anything craft related. I didn't even trust the microwave in our college dorms because people were always sticking weird crap in there for fun.
posted by JJ86 at 7:44 AM on September 20, 2010

Best answer: The real risk is that the insulation on the wiring may also be damaged, which could lead to a short circuit. I wouldn't trust it.
posted by grizzled at 8:30 AM on September 20, 2010

Best answer: Inamorata here -- although I appreciate being backed up by the Mefi community, I'm curious about claims of potential contamination. How would toxic residues actually get into the food? It's not like the microwaves are capable of carrying actual particles, right? So far, I think grizzled's answer is the most convincing, since it provides an actual mechanism by which this microwave could be dangerous.

In other words, I want to win this argument for real, which requires more than just the vague, unsubstantiated threat of toxins. (Though that may be enough to convince foursentences to junk the thing, since I suspect he does not want to even remotely risk poisoning me.)
posted by pluckemin at 9:00 AM on September 20, 2010

Best answer: Smoke from burning materials leaves a residue on the interior of the microwave. Air currents from cooking food within the microwave may dislodge that residue and it could end up on your food. Will it happen? It remains a pretty good possibility. Of course that is unsubstantiated but it follows from knowledge of heating materials which can be released into the air. If someone knew what the "char marks" were from a more precise guess could be made. Was someone trying to boil some mercury or sodium or meth? It could be they were from a simple wiring mishap but that is just as much a guess as anything. It would also be a vague assumption to think it was non-toxic.

The only way to know for certain is to hire a testing firm to analyze the air in the microwave for the presence of various toxins. Of course it is much cheaper to buy a new microwave. For the amount of money a testing firm will cost you, a very nice microwave oven can be purchased.
posted by JJ86 at 1:08 PM on September 20, 2010

Response by poster: Huh! Air currents, meth, and insulation. Thanks all; I'll junk the thing. Inamorata, memail me to remind me which microwaves of our microwave collection we didn't get for free.
posted by foursentences at 9:27 AM on September 22, 2010