White vintage clothing that has been stored improperly can develop yellow age spots, especially if it has been exposed to water or smoke or was not clean when it was put away. If the fabric is not too fragile, you can remove these spots yourself rather than taking the garment to a dry cleaner. Although traditional chlorine bleach can damage the garment, hydrogen peroxide-based oxygen bleach may lift out stains without compromising the delicate vintage fabric.
Wet a soft toothbrush and rub it over a bar of laundry soap to work up a lather. Gently work the lather into the age spots with the toothbrush and allow the garment to sit for 30 minutes. Rinse the soap off with running water.
Fill a bucket with very hot water and add a scoop of oxygen bleach. Stir the water to dissolve the bleach. Immerse the garment and allow it to soak for four to six hours.
Pour out the water and refill the bucket. Add 1 cup of white vinegar and allow the garment to soak for another 30 minutes.
Remove the garment from the bucket and wash the garment by hand in mild laundry detergent. If the fabric is thick and sturdy enough, with no threadbare spots, wash it in the washing machine on the delicate cycle.
Hang the garment in the sun to dry. Remove it as soon as it's dry and press it with an iron or steam it with a garment steamer to remove wrinkles.