Drop cloths are intended to soak up moisture. … So if you intend for your drop cloth curtains to live outdoors, know that they will mildew. Washing them frequently could help, and there may be products that help the drop cloths resist this, but it will not be the simple “hang up and be done” project you were hoping for.

How do you get mildew out of drop cloths?

Moisten a cloth with undiluted white vinegar or hydrogen peroxide, which helps disinfect and deodorize fabric; blot the mildew with the cloth until the stain lightens.

How do you wash drop cloth curtains?

If you have felt these drop cloths before they are pretty stiff when you buy them. I just washed mine in hot water with detergent and dryed them. They soften up really quick and the more you wash them the softer they get.