Finding mould on your curtains is disheartening. Not only does it ruin the appearance of the curtains, leaving mould untreated can have adverse health effects. Not all curtains are the same, so it's important to check the care label to see if your curtains are machine washable or not. Either way, you can remove mould from the fabric with the right cleaning products.
Fill an empty spray bottle with water. Wet down the mouldy spots with the water.
Sprinkle powdered washing powder onto the mould spots. Use your hands to thoroughly rub it into the fabric.
Wash the curtains in the washer in either hot or warm water, depending on the recommendation of the care label. (If the curtains must be washed in cold water, skip to Step 5.) Add 1/2 cup of chlorine bleach (for white fabrics) or oxygen bleach (for coloured fabrics) to the water. Check the care label to find out which type of bleach is safe for that particular fabric.
Put the curtains in the dryer or hang them dry --- whichever method is recommended on the care label.
Mix 1 gallon of warm water and 1/4 cup of oxygen bleach into a bucket if the curtains must be washed in cold water, rather than hot. Let the curtains soak for 30 minutes, and then wash with washing powder in the washing machine. Hang or machine dry the curtains.
Fill a bucket with 2 cups of hot water. Add 1/2 cup of borax powder, and stir it up until the powder dissolves completely.
Dampen a sponge with the solution. Sponge the borax solution onto the mould spots.
Allow the solution to sit on the curtains for several hours until they are dry. Rinse the spots with a clean, damp sponge.