Mildew is a fungus that grows from spores of mold. It appears on many surfaces, including natural fabrics like wool. Mildew starts to grow on wool when conditions are damp and warm for several days. Mildew will continue to grow and spread until the spores of mold are killed, causing damage and rot your wool. In addition, because mildew can be toxic to your health, you should not ignore it. Take care of the mildew immediately.
Be safe. As soon as you see or smell mildew, take the item outside to remove the mildew outside. This way, the mold spores are not released into your home. Also, wear rubber gloves, safety glasses and a mask.
Allow your wool item to sit in the sun and dry. The mildew will dry out also and turn into a powder. Then, brush or wipe off the mildew powder onto some old newspaper or into a bag. Throw the newspaper or bag away in an outside trashcan. This process may remove your mildew completely. If not continue on to one of the following three steps that best fit your needs.
Wash your washable wool item with lemon juice and salt. If the mildew has not thoroughly been removed, you can mix some lemon juice and salt and apply it to the wool where the mildew is and let it sit out in the sun to dry. Then rinse it in water and let it air dry. Be sure to test this method on a seam or underneath first to make sure you do not damage your wool.
Wash your washable wool item with non-chlorine bleach. Look at your label first to make sure this is safe to try. Add one tablespoon of the non-chlorine bleach to one pint of warm water. Use a sponge to soak the mildew area and allow it to sit for a half hour. Then rinse with water and allow it to air dry.
Take your non-washable wool item to the dry cleaners. If the mildew is there after brushing it off, then you will need to take it to the professionals. Tell them that your wool has mildew when dropping it off.