I have never tried this, but it sounds like you could use a degreaser or soap to try to remove the chalk.
Chalk markers will not come off car windows with normal cleaning methods. You can use a gentle cleaner and a microfiber cloth to clean the window.
One way to remove window chalk is to use a liquid soap. Another way is to use a cloth dampened with water and mild soap.
Chalk is not a porous material and does not absorb water or chemicals. Wiping it off with a dry cloth will remove any chalk residue.
Window markers are not designed to damage car paint. They are made of a soft rubber material that is easily removed with soap and water.
Chalk markers are safe to use on cars, but you should avoid getting them on the windshield.
Chalk paint does not wash cars.
Chalk is a powder and will easily rub off of glass if you apply too much pressure. To remove chalk from glass, use a cloth or paper towel to gently wipe the surface clean.
If you have a cloth or paper towel, wet it and wring it out. Then use the towel to blot the paint until the marker is gone.
Window paint is a type of paint that is designed to resist rain and other weather conditions. A car wash will not be able to remove window paint.
