Grey Deck Cleaner


GREY DECK CLEANER is a powerful oxalic acid wood cleaner and deck wash. It’s ideal for cleaning grey or blackened timber caused by weathering and mould. It can also remove light stains from water, dirt or iron without damaging the timber. The result is a clean timber surface ready for oiling with Aussie Clear or Exterior Pine Clear.

Key Points

  • The crystalised product allows for a greater volume of the final solution.
  • Works well with Aussie Clear products


Recommended Uses

GREY DECK CLEANER is ideal for use as a deck wash for cleaning grey or blackened decks and all other exterior woodwork. It can be used to remove iron staining provided that any iron particles have been sanded out. It is suitable for use on all timber species including but not limited to Ironbark, Merbau, Spotted Gum, Western Red Cedar and Treated Pine. Timber which has been previously coated with pure Linseed Oil or some other similar finish may require light sand prior to the use of GREY DECK CLEANER. In this case, vigorous scrubbing with the Oxalic Acid solution will be required clean off the discolouration caused by mould.

Directions For Use

  1. Dissolve 500 g of GREY DECK CLEANER in 5 litres of water (i.e. a 10% solution).
  2. Using a stiff brush, clean weathered timber using the mixed solution.
  3. Wash the timber down thoroughly afterwards with water or a high-pressure cleaner. This process may have to be repeated for timber that has weathered for some time.
  4. Ensure the timber being cleaned is allowed sufficient time to dry before the application of oils or paints.



1 KG of Preschem GREY DECK CLEANER when made into the solution will treat approximately 18-20 m2

Clean Up

Clean applicators in water.

Technical Data

Appearance Transparent white crystals
Molecular Weight 126
Melting Point 101°C
Specific Gravity 1.65
Odour Nil


Grey Deck Cleaner is packaged in 1kg plastic jars.

Safety Directions And First Aid

The oxalic acid crystals are poisonous and are corrosive to the skin and eyes, wear gloves when handling the crystals and the diluted solution. Avoid contact with skin. Do not spray the solution, as the mist is a severe irritant to the respiratory tract. Store in a cool dry place and out of direct sunlight. Store away from oxidising agents and food stuffs. Was contaminated skin with plenty of water. Irrigate eyes with copious quantities of water for at least 15 minutes. If ingested give water to drink. Do not induce vomiting. Seek immediate medical assistance.
CAUTION: Reacts explosively with strong oxidising materials.

SDS and Tech Data

Grey Deck Cleaner SDS
Grey Deck Cleaner Tech Data



Ross W.
Review by Ross W. on 17 Dec 2021 review stating Great Service
It was easy to apply and I am very happy with the product.

Related Products

Aussie ClearExterior Pine Clear


Why isn’t it supplied in a liquid package?

Crystallised product added with water means that the small container has the same volume as a container 10 times its size. And who wants to pay top dollar for all that water?

Will it stop my deck from being slippery in the rain?

Yes, most of the weathering and mound, removed by Grey Deck Cleaner, makes the timber slippery when wet.

Can I use Aussie Clear Oils without prepping with Grey deck cleaner?

Yes, if the deck has dark spots best to apply a coat of GDC prior to using the decking oil.

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