There are two schools of thought about cleaning siding.
Cleaning exterior wood for painting.
If there are creases or hard to reach small places on your wooden surfaces use a small scrub brush or toothbrush to clean it.
If you re using latex paint that will be water and clean rags.
Caulk after you stain or prime.
Before painting new wood sand all surfaces and edges lightly to smooth the grain.
Take the damp cloth and rub it along the painted wood working to reach the edges and corners as well.
When you re satisfied with the wood s appearance rinse the exterior from top to bottom with a garden hose.
Move the rag in small circular motions as you remove any obvious dust from the surface.
Then remove the sanding dust and apply a suitable primer.
Flat surfaces such as moldings and soffits can be easily sanded with a belt sander.
Clean the wood surface thoroughly.
Try working from left to right to ensure that you clean off the entire painted surface.
Before you reach for your paint always make sure you have something close at hand to clean up spills.
Wipe the surface with the palm of your hand.
If mildew is a common problem on your exterior wooden surfaces consider repainting with a paint designed to prevent mildew.
Wipe down the wood in smooth circular motions.
If you plan to paint sand or power wash the wood to smooth siding that has been exposed to the weather for more than a few weeks.
Scrub off the chalk with a strong solution of water and spic and span or tsp detergent or a nonphosphate tsp alternative.
Use a new bottle or one that has been filled with only plain water to prevent the tsp and bleach from interacting with residue from any leftover.
Use a long handled scrubber brush and a mild detergent to gently scrub away accumulated dirt grime mold and other residue.
Stain bonds well to unpainted weathered wood.
Give the surface a full day to dry before moving on.
Clean it by hand for a slow but deep clean job or clean it with a power washer for a faster but less thorough job.
If you plan to paint or use a solid color stain set any nails that the carpenters missed below the surface and fill the nail holes with caulk.
A simple exterior paint prep step but one that can save you an immense amount of aggravation.
Pour the cleaning solution into a spray bottle.
For larger structures a wire brush is an easy way to knock off the remaining pieces of paint and surface fibers while also roughing up the wood s surface for better paint adhesion.
Some exterior paints such as those used on aluminum siding intentionally chalk for self cleaning.