My great-grandmother Jenny (1883-1940) knew how to get rust stains out of laundry. In her handwritten cookbook, she left a proven treatment method for this type of stain. Lemon juice plays a key role in this. I still use this technique today. The treatment with lemon juice and salt even lets over 100 years old rust stains on historical linen or white cotton fabrics disappear.
1 lemon, juice
Cooking salt
Sunlight
Water
1. The rust stain on materials such as white cotton or linen is rubbed vigorously with fresh lemon juice. With lace, you just dip in the material and then sprinkle it lightly with salt.
2. The material moistened in this way is then exposed to the strongest sunlight and after a few minutes the stain is gone.
3. Rinse well in pure water.
Note: This method can be repeated several times if you have got to treat very old rust spots. They will completely fade away in the end.