I needed a vessel to hold a little chlorine bleach while I attacked some bathtub mold. I used a crappy, but still usable, old aluminum (or aluminum alloy, I suspect) cooking pot that once was coated with teflon. The teflon is mostly worn away, so that there is largely bare metal at the bottom of the pot now.
I added the bleach. There was no immediate noticeable reaction, but after I was done, about 20 minutes later, I noticed that a tough, white, almost plastic-like coating had formed on the metal pot bottom. I also noticed that the bleach was not as effective as it usually is.
Did I effect some sort of reaction between the bleach and metal that rendered the bleach less potent? And what is the white deposit? Can I remove it? Must I remove it if I want to keep using the pot for cooking?
You made Aluminum hydroxide and aluminum chloride out of your pot.
Bleach has a pH of about 12, which is high enough to disrupt the aluminum oxide layer on your cookeware. Naked aluminum is reactive stuff.
If I was you I’d throw it away. It’s likely to be pitted (microscopic perforations, which at this point will most likely not go all the way through) and not last much. Would you rather throw it away now and “lose” some hours utility, or do so after it’s started “peeing” hot contents on your hand?