A clay bar glides over lubricated paint and pulls out bonded contamination, rail dust, overspray, tree sap residue, that washing leaves behind. Paint feels glass-smooth afterward.
The baggie test
Wash the car, then put your hand in a plastic bag and feel the paint. If it feels rough or gritty, that's bonded contamination a clay bar removes.
Why it matters
- Wax and sealant bond better to clean paint
- Polishing works better without grit in the way
- Paint looks and feels smoother
When to do it
Before waxing, sealing, coating or paint correction, or any time the paint fails the baggie test.