Rather than paying for an advertisement to sell a car, many people simply paint a sign on their car window. Everywhere you drive and park, people will see your sign. Once you sell the car, you will need to remove the paint from your window. Applying permanent paint, such as acrylic, requires scraping the glass with a razor, which could create scratches. A better method involves using washable paint for ease of removal.
Select a visible spot on your window, but one that won't impede your vision while driving. You will need to paint on the inside of the window to prevent the paint from dissolving in the rain or snow. Clean the glass where you plan to paint your sign with glass cleaner and paper towels.
Mix powdered tempera paint with a little bit of water and a dash of liquid soap in a mixing container. Select a dark color to give your sign more contrast and visibility. Stir thoroughly. Add extra paint or water to make the right consistency. Window paint should be fluid enough to paint a line, but opaque enough to cover the glass. Test your paint on the glass. Remove your test lines with glass cleaner and paper towels.
Tape your sample sign next to the area where you will be painting. You will need to write backwards on the glass for your sign to be legible from the outside of your car. Use lettering brushes to make clean lines and letters. Refer to your sample often to make the process of writing backwards easier.
Check your sign from the outside of your car. Fix any mistakes by removing them with a little bit of window cleaner applied to a rag. Repaint to make corrections.
Remove the painted sign at the appropriate time by wiping the paint off with a rag and a mixture of vinegar diluted with water.
