Oxalic Acid Solution: You can spray this on your deck with a garden sprayer. This product should only be left on for about 30 minuets before washing off with a 3000 lbs - high pressure washer.

Sodium Phosphate (Sophistic acid): which you mix with water and spray on your deck with a garden sprayer. This product should only be left on for about 20 minutes before washing it off with a 3000 lbs - high pressure washer. This product works great on grease stains are acid based cleaners and you should always wear eye and hand protection. These products will not harm your plants or lawn. The 3000 lbs - high pressure washer can be rented for about $40 a day at your local rental center Be careful not to get the nozzle of the washer too close to the deck because it could cut into the wood When pressure washing, lift the wand up and away when you pass back and forth over the deck. This will keep the wand from making cleaner spots in the wood. You want an even cleaning for a professional job.

Note: Do not use bleach or fungicides on your deck. They will harm the wood and inhibit a sealer from absorbing and holding to the lumber. Just keep you deck free from leaves and dirt and you will only have to clean it every two years.

Before applying a stain or sealer, wait for 48 hours of good weather.  Start out by covering the surrounding landscaping with old cloth sheets. Plastic will create a green house effect and burn the plant life. Tape off the windows with newspaper so you won't get any over-spray on the glass. If you're worried about the siding, then tape off the bottom 2-3 feet along the deck.

Tip: To keep your deck from turning gray, you will have to purchase a sealer or stain with a (UV) ultra violet protecting chemical.

SEALING
If you are using a clear sealer, you will most certainly expect to repeat this process every year. You can easily apply the sealer with a garden pump sprayer (1-2 Gallon). Fill the sprayer over a garbage bag so you don't get any spill over on the ground.

Tip: The trick to using a sprayer and not wasting your sealer is to do the railing first from on top of the deck. Spray to the side on a 45 degree angle LIGHTLY UP AND DOWN. Then do the outside of the rail that you didn't cover. All the over-spray from spraying the rail will almost cover 2-3 feet of the floor behind the rail.

Note: Always back roll the floor with a roller to stop puddles of the sealer from forming. If you let the puddles of sealer dry, they will tend to have a milky color or even crystallize.

STAINING
When staining a deck we would recommend not using a sprayer. If your over-spray gets on the house and dries, it will be hard to remove without damaging the exterior. Use a roller for the floor and a brush for the railings and benches.

Stains are either "tinted" (they just enhance the wood color) or "semitransparent" (these are to mask over the wood grain and have a more bold look). Most deck stains are sealers mixed with a stain and can be applied in one step. If your stain is not a sealer you will have to seal also. The longest lasting stains are the most opaque "semitransparent"; they tend to last for two or three years.

Note: The same rules for Sealing apply to Staining. Always back roll the floor with a roller to stop puddles of the sealer from forming. If you let the puddles of sealer dry, they will tend to have a milky color or even crystallize.

Tip: A rag or sponge works well for applying stain to the railings.