Gently pry your ornament balls apart. These balls come in many sizes in craft stores, especially around the holidays. Plan ahead and get them at a discount after the holidays for use in your spring garden landscaping.
Rub the inside if each keepsake ball with a cotton ball covered in rubbing alcohol. This removes dirt and grime that may prevent your paint from sticking.
Lay the ball halves side by side like bowls. Dip a sponge brush into your lightest paint color and drizzle it all over the insides of the balls. Don't cover the entire surface; just create a few interesting patterns.
Drizzle paint in ever-darker colors until the sphere halves are coated. To truly get a holographic look, use pearl paint followed by metallic and glitter. Use different shades of the same hue so the ball looks like it has depth and texture.
Let the balls dry in the sun with the painted sides facing up. If you dry them bowl-side down, the paint will slide off with condensation.