Start outdoors if possible: brush off as much dry, surface mold as you can with a stiff brush before bringing the bag near other fabric or into an enclosed space, since disturbing mold can release spores that are best not spread indoors.
A solution of diluted white vinegar — roughly one part vinegar to four parts water — applied with a cloth or soft brush is a genuinely effective, fabric-safe treatment for canvas mold, since vinegar’s acidity kills most mold and mildew without the harshness of bleach, which can damage canvas fibers and color over repeated use.
After treating, the bag needs to dry completely in a well-ventilated area, ideally with some direct sunlight, which naturally inhibits mold regrowth — canvas sealed away while still damp after cleaning is exactly how the mold problem started in the first place, and skipping thorough drying risks it returning.
Last reviewed 26 August 2026