Ensure that the glass is clean by using a glass cleaner or soap and water with a micro fiber cloth. Apply using very thin coats, allowing the paint to dry for 1 minute between coats.Apply up to 5 coats to achieve the desired mirror effect.nsure that the glass is clean by using a glass cleaner or soap and water with a micro fiber cloth. Apply using very thin coats, allowing the paint to dry for 1 minute between coats.