Wipe each stone down with soap and water. Then, wipe each stone down with a rag dipped either in water, acetone, or isopropyl alcohol.
[header] How to make glow in the dark stepping stones [title] Clean the stones. [step] If you are applying paint, you need a clean surface to start with. Dust and dirt under the paint will cause problems with adhesion and you will end up with flaky paint.