If the clay bar isn't removing all the contaminants, here are some potential reasons and solutions:

1. Not Enough Lubrication: Ensure you're using plenty of clay lubricant. Insufficient lubrication can cause the clay to grab onto the surface rather than glide smoothly.

2. Old or Dirty Clay Bar: If your clay bar is worn out or contaminated, it won't be effective. Make sure to regularly knead or reshape the clay to expose a clean surface.

3. Technique Issues: Apply gentle pressure and work in small sections. If you're pressing too hard, you might damage the paint instead of removing contaminants.

4. Heavy Contaminants: For stubborn contaminants, consider using a more aggressive product, like a detailing spray or a chemical decontaminant designed for tough spots.

5. Multiple Passes: Sometimes, you may need to go over the same area multiple times. If contaminants remain, consider switching to a new piece of clay.

If you've tried these and still face issues, it might be worth consulting a professional detailer for deeper cleaning techniques.

How does clay remove contaminants?

A clay bar is an engineered, clay-like product that pulls contaminants like water spots, brake dust, metal dust, industrial pollution and road grit from your clear coat. When used with a clay lubricant, these contaminants come loose from your car and get stuck safely in the clay so they don't damage your clear coat.