How do I wash a car properly?

Car paintwork is damaged mainly by its own dirt being dragged across it. Every wash where grit stays on the mitt puts fine scratches into the clear coat, and those scratches are what dull a finish over years. The two-bucket method exists entirely to prevent that.

What you'll need

• Two buckets
• Car shampoo (not washing-up liquid)
• Wash mitt
• Hose
• Microfibre drying towel
• Grit guards (optional)

Step by step

1. Work in the shade on a cool panel.Direct sun dries shampoo and water onto the paint, leaving spots that are hard to remove.
2. Rinse the whole car thoroughly first.This removes the loose grit that would otherwise be dragged across the paint. It's the step that prevents most swirl marks.
3. Set up two buckets: one with shampoo, one with plain rinse water.Grit guards in the bottom of each help trap what falls off.
4. Use car shampoo, not washing-up liquid.Washing-up liquid strips wax and protective coatings and is harsh on trim and seals.
5. Wash from the top down, one panel at a time.Dirt runs downward. Working top-down means you're never washing a clean panel with dirty water.
6. Rinse the mitt in the clean-water bucket after every panel.This is the whole point of the second bucket. It keeps the grit out of the shampoo and off the paint.
7. Do the wheels last, with separate equipment.Wheels carry brake dust and the coarsest grit. Never use the same mitt on wheels and paint.
8. Rinse the whole car and dry with a clean microfibre drying towel.Air drying leaves water spots, particularly in hard water areas. Pat and drag gently rather than rubbing.

Tips

• Automatic car washes with brushes are the most common cause of swirl marks. Touchless washes are gentler but less effective.
• A pre-wash snow foam left to dwell lifts a lot of dirt before you touch the paint, which reduces contact damage further.
• Wax or a sealant a couple of times a year makes the car easier to wash and helps water run off rather than spotting.
• Bird droppings and tree sap are acidic and can etch clear coat within days. Remove them promptly rather than waiting for the next wash.

Common mistakes

• Using one bucket — Grit accumulates in the shampoo and gets ground back into the paint with every pass.
• Washing without rinsing first — You drag loose grit across dry paint, which is the fastest way to scratch it.
• Using washing-up liquid — It strips wax and protective coatings and dries out rubber and plastic trim.
• Washing in direct sun — Shampoo and water dry on the panel and leave spots that require polishing to remove.

Questions people ask