I had two small rust spots on a white cotton sweater. I used Bar Keeper's liquid cleaner on it. I dabbed it on and let it sit a day and then laundered as usual. It didn't harm the fabric and completely removed the stain.
Look into Genesis 950. I know it removes rust from carpets, so I don't see why it wouldn't work on fabric.
Pour salt on the stain. Then cut a lemon into quarters and squeeze the juices over the salt on the rust stain.
Lay it outside until it dries. Brush off the salt.
Put the rust stained fabric on a towel.
Pour an enzyme laundry detergent on the rust stain.
Rub the detergent into the fibers of the fabric.
Launder according to garment directions or as usual.
Add your voice to the conversation. Click here to answer this question.