This is an issue that gets worse when mold in environment gets worse. (I hope that I can move to a clean place and STAY! I have moved 10 times in 10 years usually moving due to mold.) I wear expensive WIFI protective clothing, and I am yellowing it.
I wear a black t-shirt under it when I can, and I am still yellowing it in a day.
Most of the clothing is white cotton with a fine silver thread. The silver washes out fairly easily to do hard core cleaning.
I didn't yellow clothes before Lyme. I thought that happened to people who didn't shower daily.