I poured some bleach on a rag and started scrubbing.
The rag got really hot after 30 seconds.
Just to make sure it wasn’t the friction between the rag and the toilet seat, I took the rag, set it on the counter, and poured bleach on one part of it.
Sure enough, the part I poured bleach on was hot to the touch, unlike the rest of the rag.
The rag was part of a pair of old jeans.
Is there something in jeans that reacts with bleach?
More likely the blue dye. The whole point of bleach is to turn colored chemicals into colorless or white chemicals, and when it works, that is a chemical reaction, and it may be exothermic.
when you use bleach to bleach something whiter, you use it in a diluted manner (from the already diluted concentration in the bottle).
there was a fashion, to severely spot fade jeans, with a more concentrated amount of bleach. if someone did this with too concentrated amount and/or for too long then they would have a hole in the fabric where the bleach oxidizes the fibers to death.
Bleach works fast on jeans. I dribbled a bit of fairly strong bleach water on one leg of a pair of jeans, and went inside immediately to wash them, but it left a very prominent streak.
I thought maybe I should do some more on that one leg, washing often between applications, and see if I could start a fashion for one-leg spot-faded jeans. Is anybody with me?