Yes, you should dry your car before using a clay bar. The process of claying a car involves removing contaminants from the paint surface, and it's essential that the car is clean and dry to ensure the clay bar works effectively.

Here’s a brief overview of the steps involved:

1. Wash the Car: Start by thoroughly washing your car to remove dirt and grime. This step is crucial as it prevents scratching the paint during the claying process.

2. Dry the Car: After washing, dry the car completely. This helps to avoid any water spots and ensures that the surface is ready for the clay bar application.

3. Use Lubricant: Before using the clay bar, spray a lubricant on a small section of the car's surface (about 2-3 feet square). This lubricant is essential as it allows the clay bar to glide smoothly over the paint without causing damage.

4. Clay the Surface: Gently rub the clay bar over the lubricated area to lift contaminants.

5. Final Wash: After claying, it's recommended to wash the car again to remove any residues left by the clay bar.

Here are some images that illustrate the clay bar process:

Following these steps will help ensure that your car's paint is smooth and ready for waxing or polishing after claying.