Moisture left to sit on metal will oxidize and create rust. When the rusty object comes in contact with fabric, the rust will transfer onto the item and leave a difficult to remove stain. You typically cannot remove rust stains from fabric with a simple washing. Furthermore, the longer the rust is allowed to sit on the fabric, the more difficult removing it becomes. Fortunately, you can still remove the rust stain with the help of a few common household items.
Vinegar and Salt
Place a towel flat on a level surface in direct sunlight. Lay the fabric on the towel with the rust facing upward.
Dampen the rust with white vinegar. Sprinkle table salt on the area and rub into the spot with your fingers.
Let the rust spot sit in direct sunlight for 15 minutes. Launder the fabric as you normally would.
Lay a towel out flat on a level surface in direct sunlight. Place the fabric -- rust spot facing upward -- on the towel.
Saturate the rust with lemon juice. Use your fingers to rub the lemon juice into the rust stain.
Allow the fabric to sit in direct sunlight for 10 to 15 minutes. Rinse the lemon juice off the fabric under cold, running water. Launder as you normally would.
Commercial Rust Remover
Dampen the rust with a commercial rust remover. Familiarize yourself with the instructions and warnings printed on the label.
Let the rust remover soak into the fabric for 15 minutes. Hold the fabric under cold, running water to rinse the remover off.
Launder the fabric as you normally would.