It’s disheartening to pull your cotton T-shirts from the wash only to find they’re covered in rust or water marks. Rust and water marks can be caused by mineral deposits in your water, from the zippers or accessories on other clothing, or from the water used to wash the clothes sitting too long in the pipes. Regardless of the cause, you don’t have to throw away your cotton T-shirts. Remove the rust or water marks with simple home remedies.
Apply a laundry pretreatment product to the water marks. Fill the washing machine with hot water and add laundry detergent. Utah State University Cooperative Extension recommends adding four times the amount of laundry detergent than you would use for a normal load, as well as one cup of non-precipitating water condition such as Spring Rain or Calgon.
Put the stained cotton T-shirts in the washing machine. Swish the shirts around with your hands to mix up the water conditioner, detergent and water and to thoroughly wet the T-shirts. Let the shirts soak overnight.
Run the shirts through the drain and spin cycle on the washer the next day. Run the shirts through a normal wash cycle with no detergent but with one cup of non-precipitating water conditioner. Repeat until the rinse cycle runs clear.
Use an iron if the water marks persist. Good Housekeeping suggests laying a water-stained T-shirt inside out on a white or light-colored towel on top of an ironing board and using heat to remove the water stains. Moisten a clean rag to wet the water mark with water, then run a hot iron over the area until the water has dried. Repeat this process, moving the stained part of the shirt to a dry portion of the towel until the mark is completely gone. If there is a ring around the water mark after it has been removed, rub the back of a spoon over the ring until it disappears.
Fill a tub or sink with a mixture of one part lemon juice and one part warm water. Use enough water and lemon juice so the rust-stained part of the shirt will be completely covered.
Put the cotton shirt into the lemon juice and water solution. Let it soak for 30 minutes.
Remove the shirt and launder as usual.
Apply full-strength lemon juice or white vinegar to the rust spot if it’s still there after soaking and laundering. Sprinkle salt over the spot, then rub it in with your fingers. Lay the shirt in the sun to dry, then launder as usual. Repeat this process until all of the rust is gone.