Disassemble the picture frame by removing the back, any photographs and the glass front.
Clean the picture frame, if necessary. If you want to paint the frame, you should do so now and set it aside.
Clean the Glass
Clean the glass with soap and warm water. Rinse and dry thoroughly.
Lightly Sand
With 80 girt sand paper, lightly sand the glass. Use a clean cloth or dry paint brush to remove any dust.
Use rubbing alcohol and a paper towel to clean the glass before painting.
Paint the Glass
Using a foam paint brush, apply a thin coat of chalkboard paint to the glass. Be sure to brush in one direction. Allow the paint to dry completely (about 30 minutes).
Apply a second thin coat of paint in the opposite direction. Allow the paint to dry completely.
Apply a third thin coat of paint, if desired or necessary. Allow the paint to completely dry for at least 24 hours.
Season the Chalkboard
Once the chalkboard has completely dried, you'll season the chalkboard by taking a piece of chalk and rubbing the side of it against the chalkboard surface. Completely coat the chalkboard.
Wipe the chalkboard off with a damp cloth. Your chalkboard is now ready to use!