How to clean mildew of old silk print

A friend of mine has 5 framed oriental silk prints, they’re at least fourty years old.
Improper storage unfortunately allowed mildew to attach itself to them in spots. The majority of the surface is white, and that’s where most of the mildew spots are.
Is there any way to clean this without making water rings in the silk or cause other damage?

First, try the sun.

Second, try a dry cleaner.

What would the sun do?
i.e. how would it aid in mildew removal?

Sunlight + circulating air kills mildew better than pretty much anything else, and doesn’t do the damage that chemical cleansers can cause. If you’re able to hang the prints outside on a sunny day, you should get pretty good results.

See section near bottom for cleaning garments.

*Sun and air fabrics thoroughly. If any mildew spots remain, treat washable articles as described below. Dry clean nonwashable articles.

Wash mildew-stained articles at once with soap or detergent and water. Rinse well and dry in the sun. If any stain remains, use lemon juice and salt or another bleach. If you use a bleach, be sure to test colored fabrics for colorfastness.
Lemon juice and salt
Moisten stain with a mixture of lemon juice and salt. Spread in the sun to bleach. Rinse thoroughly.
Peroxygen bleach
Mix 1 to 2 tablespoons of sodium perborate or a powdered bleach containing sodium perborate or potassium monopersulfate with 1 pint (0.47 liters) of water. Use hot water if it is safe for the fabric; otherwise, use lukewarm water. Sponge the stain or soak the stained area in the solution, or sprinkle the dry powder directly on the dampened stain. Let solution or powder remain on the stain 30 minutes or longer, then rinse thoroughly.*

Do not use Chlorine bleach on .