The Ultimate Guide to Pressure Washing and Paint Decontamination

Place your hand on the bonnet. If it is too hot to touch comfortably, the surface temperature is likely above 50°C. You must cool the car down in the shade or wait until early morning/late evening. Applying chemicals to a hot surface causes instant drying and permanent etching.

Connect your hose to a stable water supply. In many parts of Australia, 'hard water' (high mineral content) is common. If possible, use an inline water softener or filter to prevent calcium spots. Ensure the hose is fully uncoiled to prevent flow restriction to the pump.

Adjust your snow foam ratio. In 35°C+ heat, increase the water-to-soap ratio slightly (e.g., 150ml soap to 850ml water) to ensure the foam stays wet longer. Shake the cannon bottle thoroughly to mix the solution before attaching it to the trigger gun.

Ensure you are wearing closed-toe shoes (never thongs when using a pressure washer). Check that all windows are fully closed and sunroofs are sealed. Move any outdoor furniture or delicate plants away from the 'overspray zone' where chemicals may drift.

Before adding water, use the pressure washer from a distance of 1.5 metres to blow away loose leaves, twigs, and heavy clumps of dry red dust from window seals and wiper cowls. This prevents 'mud' from clogging drainage channels later.

Always start with the wheels. Use the pressure washer to blast out the wheel arches, removing salt and mud. Use a 25-degree nozzle here for more bite. Cleaning wheels first prevents brake dust from splashing onto clean paint later.

Rinse the car from the bottom up. This seems counter-intuitive, but it allows the water to dwell on the heaviest dirt at the bottom without being diluted by run-off from the top. Maintain a distance of 30-45cm from the paintwork.

Apply a thick layer of snow foam starting from the bottom and working up. Cover the entire vehicle, including the undercarriage and wheel wells. The foam should look like shaving cream. This dwell time is when the surfactants encapsulate the dirt.

Allow the foam to dwell. In Australian summer, this may only be 2 minutes. Watch for the foam starting to 'break' or dry. Do not let it dry. If it begins to dry, mist it lightly with water or a fresh layer of foam.

While the foam is dwelling, use a soft-bristled detailing brush to agitate window seals, badges, fuel filler caps, and grilles. The foam provides the lubrication needed to prevent scratching these delicate areas.

Now rinse from the top down. Use overlapping horizontal strokes. The pressure washer's force, combined with the emulsified soap, will strip away the bulk of the contamination. Pay extra attention to door gaps where red dust hides.

Apply a second, thinner layer of foam. This serves as the lubrication for your contact wash. Using foam instead of a bucket of soapy water ensures fresh lubrication is always present on the panel.

Using a high-quality microfibre wash mitt, gently wipe the panels. Use the 'straight line' method (no circles). Rinse the mitt in a bucket of clean water after every panel to ensure no trapped grit is dragged across the paint.

Remove the nozzle or use a 'sheeting' technique with a garden hose. This allows the water to flow off in a single sheet, leaving less water on the surface and making the drying process significantly faster.

Use a dedicated car dryer or a leaf blower to blast water out of side mirrors, door handles, and lug nuts. This prevents 'weeping'—those annoying drips that cause streaks and water spots later.

Gently pat the remaining droplets with a large microfibre drying towel. Do not rub. In low humidity, work quickly to prevent the minerals in the water from etching the clear coat as they dry.