So what does that have to do with vintage clothing?
It just so happens that lemon juice and sunlight have the same effect on natural fibers like cotton and linen. Lemon is gentler than chemical bleach, so it's a good first resort for removing stains form delicate vintage items.
Just as with regular bleach, this should ONLY be used on WHITE fabrics.
Simply rub lemon juice (fresh is best) into the stain, leave the stain in direct sunlight for a day, and wash with a gentle soap and water.
(As always, leave cleaning and stain removal of antique and rare vintage items to a professional)

