How to Clean Vinyl Siding | Dirt, Mold & Mildew Solutions

A grimy house exterior makes the whole property feel neglected. Yet the fix for streaky, moldy, or dusty vinyl siding is simpler than most people think — and it doesn’t require a pressure washer or harsh chemicals. The right technique and a few household ingredients restore the original brightness without risking the moisture damage and discoloration that aggressive cleaning methods cause. Here is the exact process, the solutions that work for different stains, and the mistakes to skip.

What Cleaning Solution Works for Each Type of Siding Stain

The cleaner you need depends entirely on what you are removing — general grime, mold, or stubborn spots each require a different mix. Stick to these verified ratios:

General Dirt and Pollen

Mix mild dish soap or common laundry detergent with water in a bucket. This basic solution handles most surface grime without damaging the vinyl’s finish or harming nearby plants when rinsed promptly.

Mold and Mildew

Always wear gloves and goggles when using any bleach-containing solution.

Stubborn Stains

For spots like tree sap, tar, or grease, apply mineral spirits directly to the substance, let it sit briefly, then rinse immediately. Test any solvent on an inconspicuous area first, and never let it dry on the panel.

Caution: Avoid cleaners containing organic solvents, undiluted chlorine bleach, liquid grease remover, nail polish remover, or furniture polish. Concentrated bleach can permanently discolor vinyl siding.

The Right Method: Hand Scrubbing Step by Step

The Vinyl Siding Institute and CertainTeed both recommend hand scrubbing as the safest, most effective method. A long-handled soft-bristled brush — the kind used for car washing — is the ideal tool.

1. Pre-rinse the siding with a garden hose to knock off loose dirt, cobwebs, and pollen before applying any cleaner.
2. Mix your chosen cleaning solution in a bucket according to the ratios above.
3. Start at the bottom of the house and work upward in roughly 5-foot sections. Scrubbing bottom-up prevents dirty water from streaking across clean panels below.
4. Scrub gently but firmly with the soft-bristled brush. Hard scrubbing or abrasive pads scratch the vinyl surface permanently.
5. Rinse each section immediately from top to bottom before the solution dries. Dried cleaner leaves stubborn residue that is difficult to remove.
6. Spot-clean tough stains by testing a non-abrasive scrub pad on an inconspicuous area first.

If you would rather skip mixing and need a ready-to-use cleaner that handles multiple stain types at once, check our top-rated cleaners for vinyl siding that work with this same hand-scrubbing approach.

Pressure Washing: Only With Strict Limits

CertainTeed explicitly states: “We do not recommend power washing vinyl or polymer siding as it can cause moisture intrusion, damage, and/or discoloration.” If local conditions or stubborn grime leave hand scrubbing insufficient, and your siding manufacturer permits power washing, follow these limits exactly:

• Protect plants: Rinse nearby grass and plants with water before and after washing.

A pressure washer used at the wrong angle or too close can crack panels, force moisture into walls, and void siding warranties. When in doubt, stick with the bucket-and-brush method.

Three Mistakes That Ruin a Vinyl Siding Clean

Most cleaning failures come from one of these predictable errors:

• Scrubbing top-down: Gravity carries dirty water over clean lower panels, leaving streaks. Always scrub bottom-up; rinse top-down.
• Letting the solution dry: Once detergent or vinegar dries on the vinyl, it bonds to the surface and requires hard scrubbing (or another full wash) to remove. Rinse each section immediately after scrubbing.
• Using abrasive tools: Scouring pads, wire brushes, and stiff bristles scratch the vinyl finish. Once scratched, the surface traps dirt more easily and looks permanently dull. Stick to soft-bristled brushes, sponges, or microfiber cloths.