EDITED – Rust-Stained Sails? Try This

Last winter one of my dock neighbors found a bagged sail floating in the marina.  He thought it was a bag of line, but on closer inspection discovered it was a sail, and gave it to me. When I spread it out, it looked terrible. It was filthy, rust-stained, smelly – it had obviously been in the water for quite a while. But. . .  the material was not bad. It wasn’t weak; there were no tears; all the edges were intact.  It had a wire luff and pendent at the head, and sheets attached to the clew with a snap shackle – that I couldn’t get open. Last week I spread it out again and took a stab at cleaning it. Here are some before and after photos.

Looks terrible.

Looks terrible. Really, a hopeless case.


Bottom 25 percent in mid-scrub. Most of that white color is attributable to soap suds.

Bottom 25 percent in mid-scrub. Most of that white color is attributable to soap suds.

But now. . . it's starting to really brighten up.

But now. . . it’s starting to brighten up.

I'm amazed. . .

I’m amazed. . .

Completely different!

Completely different!

Here’s what I did: first scrub was with clothes washing liquid only. I used it because, of course, the sail is fabric! Also, the clothes washing liquid rinses fairly easily and thoroughly. I used a long-handled deck brush for the scrubbing. For the second scrub, I used an OXALIC ACID solution – NOT trisodium phosphate solution (as I had originally published) – about 9 ounces of crystals (that’s all I had left from a 12 ounce box) in a gallon of hot water. I poured on as evenly as I could, then scrubbed the sail again. I left the solution on for about a half hour after the scrub was finished. Then I rinsed thoroughly, both on the ground and hoisted on the forestay, and left it to dry hoisted.

As I worked with the sail, I discovered that every one of the bronze piston hanks were seized. Some PB Blaster, a punch, and a hammer freed them all. It only took a couple of taps with the punch and hammer against the pin end to free them.  I had two failures – two of the pistons lost their heads as I pulled on them. This means that they should probably all be replaced, as they were weakened by time in the water and galvanic corrosion with the steel spring. The same thing happened with the snap shackle, so that is similarly unserviceable.

But aside from the hardware issue, which I hope to replace with salvaged parts, I think the sail is usable – and no longer ugly. It may never be snow-white, but it will be usable.  It also sort of fills a hole in my sail inventory, as it occupies about 70 percent of the foretriangle. Obviously built for smaller boat (the fabric weight is around 4 ounces), it may not serve well in high winds, which means it won’t actually be as useful as it could be, but who knows? It’s worth a trial anyway.

Everything I read discouraged the use of chlorine bleach on Dacron. Apparently bleach in any strength or dilution will ultimately weaken the fabric. On the other hand, in a situation like this, what’s to lose? Regardless, I didn’t use it. So, keep checking back, and I’ll give a report on its performance when I get a chance.

Interesting to note – as Bob Salnick reminded me in comments below – most sails are not DACRON – most are polyester, and as such aren’t subject to the same kind of severe damage and yellowing from chlorine bleach as dacron or nylon. Still, bleach is extremely corrosive and should be used in moderation. Also, Drew Fry in Practical Sailor issues some general cautions regarding the use of chlorine bleach and mild acidic cleaners when cleaning nylon and polyester line, and should probably be heeded with respect to those same materials when used in sail construction.  See the article here:  http://www.practical-sailor.com/issues/37_7/features/clean_rope_10509-1.html.


  1. Rick –
    Nice job!

    Try oxalic acid (aka “wood bleach” – you can get it at Home Depot), a weak organic acid, for iron stain removal. It’s like magic. Works with rust, or with tannic stains from vegetation (which are also iron oxide based). Works on hulls and decks too.

    I too had heard not to use bleach… on nylon… but sails are polyester, not nylon. Bleach turns nylon yellow. I cleaned a set on our O’Day 25 when we bought her (they had sat for years in 100% humidity, and were severely mildewed). I filled a child’s swimming pool with water and dumped in a gallon of bleach and submersed and scrubbed the sails, a portion at a time. Then thoroughly rinsed them. Never had a problem with them over the next 10 years…


  2. Bob, as soon as you mentioned oxalic acid, I realized my mistake in the article above. . . a senior moment, if there ever was one. I tend to get oxalic acid and TSP confused, which is what happened while writing the article.

    What I actually used was oxalic acid – I had some left over from a wood bleaching project (!) and had read that it is effective for removing rust stains. So now I need to publish a disclaimer. Thanks for your timely comment!!

  3. I’ve lost your e-mail. Please contact me. I have a sail cleaning project for PS, and if you still have dirty sails, I’ve got some ideas. Now a few comments on this post:

    Dacron is a brand name of polyester, just as Nylon is a brand name of polyamid and Kevlar is a brand name of polyaramid. I’ve learned (testing) that CLR (based on lactic acid, like sour milk) is gentler than oxalic acid (higher pH) and is nearly as effective on rust stains. As for bleach, Oxiclean is a much safer alternative for sails. It is the primary ingredient in nearly all commercial sail cleaning formulations. But that is for mildew and organic stains, not the rust you struggled with. I all cases, soaking time trumps higher concentrations, in part because rinsing all of the chemical out of the multiple layers of waterproof fabric is basically impossible, and the residue does bad things.

    • Great information, Drew. Thx. You can reach me at rickrew dot bailey281 at Gmail dot com.

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