This is a thread about removing stains from clothing and such things

i get blood on everything

I have an unsolved mystery.
For several years, I get bleach-type stains on my clothes and towels. But not all of them. Usually beige-y clothes, and the stains are slightly lighter shade of beige. Usually around the collar but not exclusively. Very dark clothes are almost never affected. I've stopped washing towels and clothes together. I have changed detergent. I have moved, so it involves multiple washer/dryers. I have used a washer cleaner treatment on my current one. I have gone through different facial soaps & topical acne treatments. Different shampoos, conditioners. The stains keep happening.
Latest wrinkle: I visited my parents, and my mom suddenly had similar stains on the back of a pair of navy blue shorts. I did do laundry at their place, but those shorts of hers were not washed after I arrived. So it must be something I brought with on my visit (either part of my body itself or any other item I brought), and it must somehow have had the chance to affect that pair of shorts. But how???