Mildew will grow on canvas items, such as tents, deck chairs, wind breakers and boat sails, if they are packed away when still damp or in unventilated areas. Mildew produces living spores which must be eliminated to prevent further growth that will cause damage to the canvas. An inexpensive, nontoxic cleaning solution can be produced using household items that will not harm the canvas. Allow the canvas item to dry thoroughly outdoors before cleaning the mildew-affected areas.
Mix 1 qt. of white vinegar and 1/2 tsp of washing powder with 5 qts. of warm water in a large cleaning bucket. Add a few squirts of lemon juice.
Dip the soft-bristled brush into the bucket of cleaning solution and scrub the mildew-affected areas until the mildew is completely removed.
Rinse the canvas thoroughly with copious amounts of clean, cold water.
Allow the canvas to dry completely outdoors.
Clean the canvas items outdoors to prevent water splashes indoors.
Allow canvas items to dry thoroughly before storing to prevent further mildew growth.