Darkoshi

While putting away dishes yesterday, I noticed some odd irregular shaped small spots on one of the Rubbermaid plastic containers (the bottom clear plastic part, not the lid). At first I thought it was food stuck to it, but washing it again, and scratching at the spots with my fingernails made no difference. It seems to be spots etched out of the plastic.

I asked my sister what food she had in the container last; baked apples with oranges, cinnamon and vanilla (hmmm, sounds tasty). So at first I thought that maybe the acid from the apples or oranges had etched the plastic, which was surprising as I'd never known plastic to be eaten away by acidic foods.

But the below thread indicates the spots are most likely from microwaving food in the container, and having the food get so hot that it melts the plastic in those spots. That makes sense, as I never microwave food in plastic containers, but my sister and niece do.

What is this white stuff on my plastic storage container?

The spots on my container look similar to the photo at the top of that page, except mine are on the sides of the container instead of the bottom, and more spread out rather than one big splot. More like the first photo link on this comment. (But neither me nor my sister has been using the dishwasher, so it has to be from microwaving.)