The yellow, orange or brown spots we sometimes find on our clothes may be caused by rust. Iron content of over .2 parts per million in your water supply can cause these type of stains, so it's important to have your water supply checked. Two possible sources can be rusty water pipes or water heaters. One way to combat this problem is by using a mechanical water softener with an iron filter. Also, using a non-chlorine bleach can help, as chlorine bleach may cause the iron in the water to precipitate on fabrics and leave stains. Lemon juice can help remove rust stains on certain fabrics.
Brush off as much as possible when garment is dry, then rinse under cold running water. Pretreat with a paste of powder detergent and water, or liquid laundry detergent. Wash using laundry detergent and a fabric-safe bleach.