Oxalic Acid Crystals

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In stock
(£13.82 inc VAT)

Oxalic Acid is used to remove dark stains, water marks & to refresh the woods colour especially oak, can also be used to remove ink stains, it is also an effective rust stain remover from concrete & metal, supplied in crystal form to be mixed with Water or Methylated Spirits to make an effective wood bleacher,

  • Remove Tannin Stains
  • Rust Stain removal
  • Water mark removal
  • 99% + purity grade
  • Available in 1Kg, 5Kg, 10Kg & 25Kg
Delivery (Free UK Mainland for orders of £60 and over)

Mainland UK postage rates

Order Value Below £60    £60 & Over
UK 2-5 Working Days    £5.50         FREE
Next Working Day    £7.50         £3.50
Pre 12 Midday    £10.20         £8.20
Pre 10am    £13.50         £11.50
Saturday    £21.50         £17.00

Click here for full postage details

We also offer a click and collect service for those who would like to order online and collect from our store here in Bidford-upon-Avon. Please select click and collect at the checkout for this service.

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Dark Spots, tannin stains & discolouration of the wood surface are usually caused by moisture and is exacerbated when the moisture is contaminated with metal, such as iron and steel (especially on Oak & Idigbo). This discolouration can be removed with oxalic acid.

Oxalic Acid can also be used to freshen wood colour if it has become lightly grayed due to external exposure to sun light. In the refinishing of wood furniture, oxalic acid can be used after stripping to lighten and soften darker stained areas before refinishing. It can also be used as a rust remover and a stain remover in many other applications.

Just hearing the word "acid" sounds ominous, but oxalic acid is easy and safe to use in the home. In fact it is found in many vegetables including spinach, and rhubarb and is also used in shampoo and washing powders.

Oxalic Acid is supplied in crystal form and looks just like sugar.

Our Oxalic Acid is a high commercial 99% + purity grade Not all Oxalic Acid for sale is the same purity.


Simply mix with water in a clean container until you have a saturated solution (where there is a tiny bit of undisolved sediment at the bottom).
Approx. 60 grams per litre of water. You then have a ready to use solution. Adding more Oxalic Acid crystals will not make the solution any stronger.

Methylated Spirits can also be used as an alternative to water. Using Methylated spirits allows for quicker drying, enabling a protective coating to be applied to the timber sooner. Do not breath the fumes.

Apply the solution directly onto the timber with a brush.

The bleaching process will continue for 1 - 2 hours, however results can often be seen within 20-30 minutes. Multiple applications may be required to fully remove the staining. Once removed, the timber will need to be thoroughly cleaned with clean water or methylated spirits and then allowed to dry.


One kilogram of Oxalic Acid will make approx 15-17 litres of ready to use solution.

Coverage is approx. 12sq meters per litre of solution (depending on porosity of the timber)

A pre mixed Oxalic Acid Wood Bleacher is also available as a ready to use solution in 150ml, 250ml, 1L, 2.5L & 5L bottles.

Please note that any surface coating such as a woodstain, paint, oil etc will prevent the oxalic acid solution from working, so all protective coatings will have to be removed prior to application.

Warning: Oxalic Acid is still an acid and should be treated with respect. In its purified form, oxalic acid is a highly corrosive and toxic substance. Latex gloves should be worn at all times when using it and it should always be mixed and used in a well-ventilated area.

Always protect your skin and wear a dust mask when mixing.

Container size: 1Kg, 5kg, 10Kg and 25kg.

Health & Safety Sheet (Oxalic_Acid_COSHH_Data_Sheet_PDF.pdf, 135 Kb) [Download]

Data Sheet (more_info_oxalic.html, 3 Kb) [Download]

Read some of the reviews after writing mine. The product must have changed since the others wrote. My black marks, really bad, All cleared and the floor looks brand new. No hassle, very easy to use. Not a person for writing reviews but this product earned it.
I ordered this a few days ago as my window cleaner had spilt water+ on my Oak floor and had left a large patch of brown marks and footprints all over my living room floor. I must admit that having tried almost everything else I didn't have much hope with this product!!!! Mixed as instructed, applied the solution to the floor. Less than 20 minutes later I was (sorry)' gobsmacked' the marks had started to disappear, 40 minutes later all gone. Pathetic, I ran to my neighbour and even she was shocked. My only regret is that I didn't take photos of it before. If I'd used my insurance it would have cost an arm and a leg as it really was a large area. All I can say is thank you, thank you, thank you. Also did my door furniture (diluted a bit more) as it had all pitted, now brand new. Try it and see for yourself. AMAZING
Oxalic Acid is brilliant for removing stains from oak flouring. Superb service from AG Woodcare
Seems to work well and cleared up most of the tanin stains with some light scrubbing.
Took a chance that it would lighten some wood that had been treated with wood stain. Pleased with result although hasn't stripped it entirely-but wasn't expecting it to anyway.
I am using the crystals to control varroa mites in my beehives. I heat it and the vapours circulate inside the hives killing the mites. the crystals are working very effectively. thanks.
great product , easy to use , i have used this product for over 45 years i think it beats similar products , and it comes with safety kit which is a bonus
Used it to remove some very stubborn rust stains from a set of dinghy sails. Worked well, removing most of the rust stains, and made the white sails much cleaner.
I used this on a beech chair which had black staining from water damage. It was easy to use and removed most of the staining so I would recommend it.
AG Woodcare Products Ltd has a good web site and the item was deliivered promptly and safely. The acid was used to remove rust stain from stone fireplace. Took several attempts but satisfied with final result. The face mask supplied didn't prevent the occasional fume from reaching me and cause a little coughing but overall seems a safe product to use. Pity a smaller quantity isn't available.
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