Laundry of shirt

I have a black shirt and when I launder it, it comes out with white marks on it. Does anyone know why this is?

What is the material of the shirt? E.g., 50% cotton, 50% polyester
.

If the water pump in your washing machine is clogged or weak (starting to fail, perhaps), then you could get laundry detergent, lint, dirt, etc. marks on your clothes due to a weak rinse.

If you habitually overload your washing machine, you can also end up with a poor rinse.

If you live in an area with hard water, the minerals in the water may be interacting with your detergents and clothes, leaving marks behind. Similarly, calcium deposits from hard water may have built up inside your washing machine to the point where small bits of calcium are breaking free and leaving marks on your clothes.

If you sweat a lot or have any kind of medical condition that causes you to sweat more than the average amount of salt, then you could be getting salt stains on your clothes.

Some of the newer high efficiency washing machines rinse rather poorly and, especially as they age and their filters get clogged, can leave residue on clothes.

It is soap residue. The outside of the drum never gets scrubbed by clothes, so there’s some build up. When the drum spins, it pulls clothes outward and some bits get sucked into the drain holes. This is where the residue is picked up. I have noticed a pattern of white spots on clothes, and nothing else explains it.

Have you tried another brand of detergent?

In my experience, liquid detergent leaves less residue than powder.

Also, if your machine is labeled as high efficiency (“He”), it uses less water than a traditional machine, and you should make sure your soap has the “He” mark.

Do you dry it in a home dryer. Could be lint from towels that have been dried beforehand.