Cleaning Mildew from Canvas

a dirty canvas tent
What You'll Need
Scrub Brush
Rubbing Alcohol
Laundry Detergent
Household bleach
Tri Sodium Phosphate (TSP)

Cleaning mildew is a task that can’t be ignored. No matter where you see it growing, once you know it’s there, it has to be dealt with. Most of the time, saving mildew covered surfaces is easy. You’ll spot it in the corner of the shower or see it creeping up as you stroll across your deck or patio, and you know exactly how to vanquish it.

But what if you found mildew on your popup tent or other outdoor gear that’s made of canvas material? It’s not unreasonable to expect this situation. After all, canvas tents and camping gear are made for the moist, dirty, open outdoors and then spend most of their downtime being folded up in questionable environments like garages, yards, or sheds. That’s a heavenly situation for a mold or mildew spore.

It can be tempting to simply give up and accept mildew stains on any canvas item that spends a lot of time outdoors. However, you can minimize the hassle of removing mildew and stains by using the following instructions and cleaning options.

Step 1 - Drying the Canvas

Even if your tent is covered in mildew, resist the urge to pounce on it and start scrubbing away. Remember that excess moisture is probably what led to this mess in the first place. So, unfurl the canvas and allow it the time to air out and dry. (Give it about 24 hours of uninterrupted dry time.)

Step 2 - Preparing the Canvas

Remove any loose material before attempting to attack the canvas mold. This includes dirt, grease, metal tent poles, and clasps if they’re mildew free, and basically anything else that isn’t either the canvas or the mildew .This prevents the loose material from being rubbed into the canvas during the later stages, saving you a great deal of extra cleaning work.

To begin, get out your stiff brush and start scrubbing superficial stains and debris. You may use a specialized cleaning brush if you have one. However, feel free to improvise solutions based on the size of the job and the things you have at hand.

Once you are satisfied that you have removed everything that it is possible to remove with a brush. Use your vacuum cleaner with a hand attachment or, you can use a hand vacuum to remove any dirty materials that may have come loose that are small and not easily visible.

Step 3 - Cleaning the Canvas

Next, kill any mold or mildew that has survived with rubbing alcohol and water, two ingredients that you should have no trouble getting your hands on. Mix the rubbing alcohol and water in equal parts in a bucket or other small container.

Dampen a rag with the mixture and rub the canvas thoroughly. You may even pick up particulate that the brush and vacuum routine left behind. (You may need to dampen the rag more than once and scrub the tent multiple times, particularly if the mildewed area is large. However, do not apply so much of the mixture that it drips or runs after being applied.)

Finally, rinse out all of the rubbing alcohol with cold water. Allow it to dry for 24 hours.

Step 4 - Finishing Up

From here, the way to proceed will change depending on what you are cleaning mildew from, in particular its size.

If you are cleaning a large object, such as a tent or awning, use water and laundry detergent to clean it by hand, rinsing thoroughly when you are done.

However, if the object is small, such as a tent attachment or shoe, you can simply put it in the washing machine to clean it that way.

Additional Methods

The benefit of using water and rubbing alcohol is that both are readily available, easy to use, and won’t harm you or your canvas. However, if you have a serious mold problem in your popup tent, shoes, or other items, consider these methods. They require a bit more forethought and attention for safety reasons, but they are effective.

Bleach Solution

A mixture of bleach and water in a spray bottle is effective when sprayed on mildew-covered canvas and wiped away with a rag. Be aware that unlike with the rubbing alcohol, you should only let the bleach linger on the canvas for short time before wiping it off along with the mold. Because there is a time factor involved, you may want to spray and wipe individual sections at a time.

WARNING: Bleach may ruin any colored canvas.

Tri Sodium Phosphate (TSP)

A mixture of 1 cup TSP, 3 quarts of water, and 1 quart of household bleach makes for a super-powered mildew killer. Just like with the bleach on its own, apply it to a moldy area, let it sit for a few moments, and then wipe it away.

WARNING: This cleaner is powerful and even works on grease, but don’t put it on everything. It’s great for canvas and certain painted surfaces, but will stain metal and wood.


Both bleach and Tri Sodium Phosphate have caustic properties that can damage eyes and skin, so handle them with care and wear the proper skin and eye protection when using them.