To paint sand dollars, clean and harden the shells, and paint your desired scene or pattern on the sand dollars using acrylic craft paint, glitter paint or watercolor paint. Spray an acrylic finish over the paint for a glossy look.

Before painting sand dollars, clean them by soaking them in water until the water becomes brown, and continue with new batches of water until the water remains clear. Soak the sand dollars in a bleach and water solution for five to 10 minutes, and rinse them thoroughly. Allow the pieces to dry completely before brushing them with a solution of one part water to one part white glue or a commercial sand dollar hardener to keep them from becoming brittle and breaking.

Next, create unique patterns with well-watered watercolor paints, which easily soak into the shell. You can also use acrylic paints to paint a picture, such as a tropical beach scene with palm trees and sailboats. For a Christmas decoration, consider painting a sand dollar with while glitter paint, or paint a snowman or Santa face. Lock in the design with an acrylic spray, letting it dry completely before tying any ribbons or other decorations to the sand dollar. The entire cleaning and painting process takes around two hours of active work, excluding time for drying.