I have just pulled my old Molle rucksack (5.11 Rush 72) out of storage and it is has a white/grey mould running through the fabric.

What is the best way to make this rucksack suitable for use again?

It is large (over 50 litres) and probably will need an industrial washer / launderette if that is the technique for cleaning.

Further details

  • 1050D Nylon
  • 210D 118T PUx2 coating
  • Has been used extensively outdoors
  • Never had mould before
  • Has been stored indoors, dry for approximately 6 months
  • Although Erik's answer will be necessary to clean it, I do not think it will be sufficient. I would write off this rucksack. A rucksack that has had mold in it, that becomes wet, will stink to high heaven, and any clothes or garments inside it will stink, as will quite possibly the tent, the sleeping bag... I'd write it off. But if you are adamant about keeping it, Erik's suggestion is the way to go. Sun and bleach.
    – Stian
    Sep 20, 2017 at 8:11
  • yes, the smell its one of the hardest things to keep away, The pack is PU coated inside, which makes it easier on that respect as it can be cleaned extremely well. The outside might be the problem. I have just plain canvas gear which I have been able to take the mildew smell off and some other gear which still has a faint smell, you are lucky this is all nylon. There are about a zillion remedies for mildew smell and on my experience they can all work, or not, depending on conditions and material of the gear. Id try to salvage it Sep 20, 2017 at 15:28
  • It would not have mold if is was stored dry. Stored in a dry area is the same as stored dry. Open all pockets and hang it for storage.
    – paparazzo
    Sep 20, 2017 at 15:35

2 Answers 2


Sun will help. You can leave it in the sun, taking care the whole affected area gets direct sun. Then, still outside, brush off all that is possible with a stiff brush. After that you can proceed to a proper wash. For the wash you can use oxygen bleach. It will have a better outcome than regular bleach. From there on it really depends on the conditions of the pack after the wash. You might have to repeat the process.

Keep in mind that even if the mould is gone there is a good chance it will smell like mildew. That is a difficult smell to remove sometimes and some discoloration can remain in the area affected.

Remember that the brush will have to be treated as the pack is after you used it on the mould.

Edit to address the residual mildew smell, which is likely to remain if the mould was a lot:

  • In conservation, commercial products that will bind the leftover chemicals causing the odour are used.
  • I tried Mirazine in the past, which always gave poor results for mildew.
  • There are home remedies, vinegar being the most common.
  • Often on boats, beside the usual commercial stuff, borax or glycol are used (plain antifreeze works too, even if it's propylene glycol). This stuff needs proper disposal after being used as a wash. The intent in this case is to remove the smell, not to use these substances as biocide. The process for that is slightly different and not applicable to the question.
  • YMMV depending on conditions and material treated.
  • Do not use Febreze or similar to cover the smell or you will end with a carousel of stenches that will drive you nuts.
  • Good suggestion. I'd also fill it with generous amounts of desiccant when storing it afterwards. Sun, bleach and very low moisture will kill/deactivate the fungus, repeated washings will reduce the amount of it in the cloth. (I still think it won't be enough, but good suggestion anyway)
    – Stian
    Sep 20, 2017 at 8:13
  • 1
    @Flint, the antifreeze thing is something we use on boats sometimes, its only for the smell, because of the way it can bind the leftover volatile compounds, not for killing it or stay on to become food, you are supposed to wash it off. Dont confuse that use with killing the mold and fighting some rot in wood, that requires a proper biocide with good penetration and purity and is supposed to permanently stay there. Some of the ingredients are the same but they are two different things used for two different purposes in two different ways. Ill try to make it clearer in the answer Sep 22, 2017 at 14:07
  • Thanks for explaining and updating your answer with this Erik. I've never heard of this and thus misunderstood the intent. This makes a lot more sense.
    – Flint
    Sep 24, 2017 at 19:56

Hydrogen Peroxide or vinegar. Freezing is a good first option. If that doesn't work, then the other two will do the trick.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.