How to Remove Rust Stains from a Cedar Fence

Rusty FenceOne of the guests who came over to comment on the post, “Should I Paint or Stain My Wooden Fence?” noted she’d put in a DIY fence some time ago. Unfortunately, she’d used nails which had bled unsightly rust stains into the wood of her beautiful new fence.

This is an upsetting situation, and more common than you might imagine.

What do rust stains look like?

Rust stains are usually these black bleeds which start spreading out through the wood around their point of origin. This is generally going to be a nail somewhere in your fence.

If you’re particularly unlucky, it will be multiple nails in your fence.

Cleaning the stain

The stains can be cleaned. You’ll need bleach:

  • Two buckets
  • Bleach
  • Trisodium Phosphate (TSP)
  • Oxalic Acid
  • One hard bristle scrub brush
  • One small paint brush

You can find all of these items at any local big box hardware store.

You’ll start by mixing the TSP, the bleach, and some water into one bucket. You’ll mix the oxalic acid and water into a second bucket.

Dip your hard bristle brush into the TSP solution. Scrub as hard as you can, getting the rust stain just as light as you can get it. If you’re lucky this will be enough, but often the best you can do here is to lighten the stain.

Once you’re satisfied this rust stain isn’t getting any lighter you can dip a clean paintbrush into your oxalic acid. Brush the acid over the rust stains. You want to use the small brush because you don’t want to get the acid on the unstained wood. Let it dry, then rinse the solution down with a hose.

If you’re lucky, the stain will be gone after this…for a little while, anyway. Those cheap nails will still be there, which means the rust stain is likely to return at some point in the future.

There is another solution.

Don’t skimp on your fence. Get a high-quality, custom fence instead, one made with commercial-grade, corrosion proof hardware. If you live in Mequon or anywhere else in the Milwaukee metro area, you can get one from us–call us today for a free quote.


  1. Alba says:

    Thank you for letting me know what this is.

    I believe that I’m going to have to remove the screws and nails and start over again. 😥

  2. TD says:

    You don’t say how much bleach and TSP to mix or what % of Oxalic Acid.

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