Building work next door, a facade renovation or a drive past a concrete plant on a broken dirt road, and grey specks of cement appear on the doors and sills. It happens especially often in autumn, when wet mortar flies off lorry wheels.
Cement is not ordinary dirt: as it sets it bonds firmly to the clear coat, and its hard particles act like an abrasive. So never scrape it off dry. Wash fresh splashes off with water as quickly as possible, and soften dried ones with WD-40 before removing them carefully.
What you will need
- a hose or bucket of clean water
- WD-40 Multi-Use
- for large areas, WD-40 Trigger Pro 591 ml
- soft cotton rags
- a plastic scraper or kitchen spatula wrapped in a clean cotton cloth
- car shampoo and a sponge
Important: Never rub or scrape dried cement without lubrication, or it will leave scratches. Do not let a metal tool touch the paint unless it is wrapped in cloth. Work in the shade on cool bodywork and keep WD-40 off brake discs, tyres and the windscreen.
Step 1
Wash off fresh splashes straight away
Before the cement sets, rinse it off with plenty of water from a hose or bucket. Pour from above, let the water run off and help only lightly with a soft cloth, without pressure.
Soaking also softens the surface of any specks that have already hardened, making the next steps easier.
Step 2
Apply WD-40 to dried specks
Shake the can of WD-40 Multi-Use and spray it onto the marks so every speck is fully covered, without excess. On sills and lower doors, where splashes are heaviest, the WD-40 Trigger Pro sprayer is quicker.
For single specks near seals and trims, the straw of WD-40 Smart Straw is handy.
Step 3
Wait a few minutes
Let the product work for 3-5 minutes. WD-40 penetrates between the cement and the clear coat, loosens the bond and makes removal easier without damaging the paintwork. Treat one panel at a time so it does not dry out.
Step 4
Lift the cement with a wrapped spatula
Wrap a plastic scraper or kitchen spatula in a clean cotton cloth and carefully lift the softened speck at a shallow angle. Move in one direction rather than in circles.
If the cement holds on, do not press harder: apply WD-40 again and wait. Wipe away any residue with a soft rag.
Step 5
Wash the car
Finally, wash the treated areas with water and car shampoo to remove cement dust and the WD-40 film. Rinse and dry the bodywork. Inspect it once more in daylight, as small specks are easy to miss the first time.
Tip: If you regularly park near a building site, use a car cover. After driving on wet dirt roads, wash the sills the same day: fresh mortar rinses off with water in a minute.
What next
Once clean, apply wax to the paintwork, especially before winter when road salt joins the splashes. The same WD-40 Multi-Use helps remove tar from sills and protects door locks and hinges from moisture.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».