Sugar Soap To Clean Timber

Can I use Selleys Original Liquid Sugar Soap on a timber deck to remove a stain — and do I leave it on?

You can use Selleys Original Liquid Sugar Soap to try to remove stains from timber. The direct answer to the second half of the question is no — do not leave it on. It should be rinsed off before it dries on the surface. And follow the directions on dilution when you prepare it.

Note the wording of the first half. Selleys says it can be used to try, not that it will work. Timber is porous, stains penetrate it rather than sitting on top of it, and no cleaner reaches what has soaked into the fibres. On a new deck it is worth an attempt before you consider sanding.

Why "rinse before it dries" is the whole answer

Sugar Soap is a salts-based alkaline cleaner. When the solution dries on a surface instead of being rinsed away, the water leaves and the cleaning salts stay behind as a deposit. On glass that shows as a hard white film. On timber — which is absorbent, textured, and often coated or oiled — you end up with dried cleaner sitting in the grain, which can leave its own mark on top of the stain you were trying to shift.

This is also why the dilution matters. Selleys Original Sugar Soap's directions call for half a cup into half a bucket — 5 litres — of water for most jobs, diluting to suit the cleaning task. A stronger mix is higher in cleaning salts, so a stronger mix left to dry leaves a heavier deposit. Stronger is not better here; on a deck it is actively worse.

What the product is

Property	Typical result
Colour	Clear blue
Density	Approx. 1.13 g/mL
pH	Approx. 11
Pack size	750 mL, makes up to 30 litres
Dilution	½ cup into 5 litres of water

Figures are indicative data only and are not intended for the preparation of specifications.

How to do it on a deck

1. Test an inconspicuous area first. A corner under a step or the back of a board tells you how the timber and any coating on it will respond before you commit to the whole deck.
2. Dilute half a cup into 5 litres of water. Mix more solution than you think you need, so you are not stopping mid-deck.
3. Work in sections you can finish. This is the practical consequence of the rinse rule — a deck in full sun dries fast, so clean an area you can rinse before it starts to dry, then move on.
4. Apply with a cloth or mop. A Selleys Super Cloth is ideal. For a stubborn or in-ground mark the product can be used neat with a non-scratch scouring sponge or cloth such as a Selleys Wash Up Wiz — but on timber, keep neat use to the mark itself and rinse it promptly.
5. Rinse thoroughly, before it dries. Clean water and a clean cloth, or a hose on the deck.
6. Let the deck dry fully before deciding whether the stain has gone. Wet timber always looks darker and more even than dry timber, and judging the result too early leads to unnecessary second rounds.

Limitations to keep in mind

• Do not let it dry on the surface. This is the specific instruction for this job.
• Wipe it off immediately from aluminium and brass surfaces. Deck hardware, balustrade fittings and light fittings are easy to splash. Bare brass and aluminium can tarnish or discolour.
• Rinse it well from glass before the product dries. Relevant if the deck runs up to glass balustrading or bifold doors — see streaking on windows after using Sugar Soap.
• Test an inconspicuous area for compatibility and colourfastness if the product is going near clothing, carpet or upholstery — outdoor cushions and shade cloth included.
• Its safety directions warn that it causes serious eye irritation. Avoid contact with skin and eyes, and rubber gloves are recommended for sensitive skin.

Common questions

Do I leave the Sugar Soap on the timber to soak?

No. It should be rinsed off before it dries on the surface.

What dilution should I use?

Follow the directions on the pack. For most jobs that is half a cup of Selleys Original Sugar Soap into 5 litres of water, diluted to suit the task.

Will it definitely remove the stain?

Selleys says it can be used to try to remove stains from timber. Whether it works depends on the stain and how far it has penetrated the timber.

Can I use it neat on a stubborn mark?

The product's directions allow neat use for stubborn or in-ground marks with a non-scratch scouring sponge or cloth. On timber, apply it to the mark rather than the whole board and rinse before it dries.

What happens if it dries on the deck?

Sugar Soap is a salts-based cleaner, and dried solution leaves a salts deposit behind. Rinsing before it dries is what avoids that.

Is it safe on a new deck?

Test an inconspicuous area first. That applies to any new or coated timber, where the finish rather than the timber determines how the surface responds.

Should I be worried about the deck's coating?

Test first. A spot test on a hidden board is the only reliable way to know how a particular oil, stain or sealer will react.

What about ongoing deck care?

See maintaining outdoor timber and decks for the broader maintenance job, and the multi-purpose cleaner range for the full set of Sugar Soap variants and their directions.