How to Remove Mold From a Tent (Nylon and Canvas)

Decide whether you should be the one to clean it

The CDC’s mold clean-up page says: “Some people are at risk of significant and even severe health effects from mold exposure. These individuals should not take part in cleaning up:” and lists “People with allergies, who may be more sensitive to molds”; “People with immune suppression or underlying lung disease, who are at higher risk of fungal infections”; and “Individuals with chronic respiratory diseases like asthma or chronic obstructive pulmonary disease (COPD), who may have trouble breathing when exposed to mold”. The CDC page is written for mold in homes and buildings, and a tent is a different object, but the people at risk are the same. If you are on that list, hand the tent to someone else.

Put on the protective gear before you touch the tent

The CDC says: “Take steps to protect your mouth, nose, skin, and eyes when cleaning up mold.” For the mouth and nose: “wear at least a NIOSH Approved N95 respirator. If you plan to spend a lot of time removing moldy belongings or doing work like ripping out moldy drywall, wear a half-face or full-face respirator.” For skin: “Wear protective gloves (non-latex, vinyl, nitrile, or rubber). Do not touch mold or moldy items with bare hands.” For eyes: “Wear goggles that provide complete eye protection. Choose goggles designed to keep out dust and small particles. Safety glasses or goggles that have open vent holes will not protect you against dust and small particles.” These are the CDC’s words for cleaning mold in general; check the label of any cleaner for its own protective-gear lines as well. The CDC also says: “You should never mix bleach with ammonia or any other cleanser.” So use one product at a time, as its label directs, and keep bleach out of it altogether (see What not to do).

Pitch the tent outdoors and let it dry

MSR sets the tent up to wash it, and a pitched tent is easier to reach on every panel. SectionHiker, a gear publication, says to stop mildew spreading by moving the gear “to a dry location and expose it to sunlight,” and warns not to leave it too long in bright sun “because the UV can also degrade or bleach colored fabric over time.” Kodiak, a canvas maker, says that if you must break camp wet, “set your tent up ASAP and let it dry out” when you get home.

Nylon or polyester: wash gently first

Gear Aid says “you may be able to remove mold with just hot and soapy water” depending on how deep it is, but its own steps use warm water: spot clean with a sponge, then fill a tub with warm water and add 2 fl oz (59 ml) of its Pro Cleaner. Big Agnes says “Never use hot water,” so use warm. Gear Aid warns: “Do not scrub the underside of the tent fly as you may damage or remove the polyurethane (PU) waterproof coating.” Then “Rinse with water until the soapy residue is gone” and “Allow to air dry completely.” Do not put the tent in a washing machine: NEMO says “Do not wash your tent in washing machines” because the fabrics and mesh will likely tear, MSR says never to machine wash it, and Big Agnes says “Do not dry clean or machine-wash.” The makers also disagree on soap. Gear Aid lists mild dish soap, while Big Agnes says never to use dishwashing liquids and MSR says to avoid dishwashing liquid, detergent and bleach. MSR also says plainly: “Unfortunately, washing a tent does not remove mold.” Use your own maker’s soap rule and follow the label on any tech wash.

Nylon or polyester: soak it in an enzyme odor eliminator, as the label says

Gear Aid’s mold guide uses Revivex Odor Eliminator (sold earlier as Mirazyme): fill a tub with just enough water to submerge the tent, add “1 fl oz of Revivex Odor Eliminator for every gallon of water,” unzip everything, and soak “for a maximum of 5 minutes.” The limit matters for a PU-coated tent: Gear Aid says the coating can break down and delaminate, “more likely if a tent is damp or has been soaking in water for longer than five minutes.” Then “Do not rinse the tent” and let it “air dry completely and away from sunlight/heat.” Gear Aid explains that heat kills the microbes and rinsing washes them away. Gear Aid’s two pages differ on method: its usage-tips page says fabrics “should soak for approximately 5 minutes” and lists tents among items that “should not be soaked but need preventative maintenance” with a spray mix instead, giving a stronger spray mix for mold or mildew smells. Follow the label on your bottle. SectionHiker’s 15-minute soak comes from a general gear walkthrough, not a PU-tent rule. Gear Aid’s tips page cautions that the product “does not guarantee the complete elimination of mold itself,” so it is a deodorizer first. It prints one more warning, “Odor Eliminator may darken leather; please patch test before use,” which matters if your tent has leather trim.

Cotton canvas: use the maker’s remover and a soft brush

Kodiak says “If you catch mold in the early stages you can save your tent,” suggests Iosso Mold Mildew Stain Remover, and says to “Follow the instructions on the label.” Montana Canvas, another canvas maker, also recommends Iosso Mold and Mildew Stain Remover, says to “Follow the directions for mixing the Iosso solution” and to scrub lightly with a soft bristle brush so as not to damage the canvas fibers or coating. Iosso does not post its label directions online, but its product page says “It is non-chlorine” and “4 oz. makes 1 gallon”; read the container for its warnings. Montana Canvas adds that “High pressure washers are NOT recommended.”

Cotton canvas: vinegar and Iosso, in your maker’s order

The canvas makers differ on order. Montana Canvas uses Iosso first and then, if mold is still present: “Use ½ cup of cleaning vinegar for every gallon of water,” scrub lightly, “Let stand for about ten minutes and rinse well,” and repeat once dry if needed; it says “We recommend doing this on a warm sunny day!” White Duck suggests spraying mild cases first with distilled white vinegar and keeping a commercial mold remover such as Iosso for the toughest jobs. Kodiak names only Iosso. White Duck says “Soap and other detergents can harm the fabric and leave deposits,” and Kodiak likewise says “Soaps and detergents can damage the water-repellant treatment of the canvas,” while Montana Canvas suggests mild laundry detergent for surface dirt. Follow your tent’s maker, and do not combine products in one bucket.

Dry it completely, in the open

Kodiak says “Storing a wet or damp tent, even for a short time, can ruin it and void the warranty.” Never machine dry a nylon tent: NEMO says “Do not machine dry your tent either, as heat can melt the technical fabrics,” and MSR says never to machine dry. For nylon tents, NEMO says to lay the tent flat or line-dry it in indirect sunlight because “Direct sunlight can damage tent fabrics if left for long periods of time.” Canvas makers lean the other way: Montana Canvas cleans on a sunny day and White Duck dries canvas in the sun. After an odor-eliminator soak, follow Gear Aid and dry away from sunlight and heat. Dry it the way your maker says.

Restore water repellency where the maker says to

Kodiak says mold and Iosso “will degrade some of the canvas water repellency” and to retreat the affected area with a silicone-based water repellent; it warns that other treatments can clog the canvas pores. Montana Canvas suggests a reconditioner called Canvak and says it does not recommend other coating products because they “can negatively react with the original treatments on the canvas.” On nylon, MSR suggests Nikwax and Gear Aid products for waterproofing repairs. If seam tape lifted during cleaning, see our guide to sealing tent seams.