Whether you plan to paint gourds or use them for crafts such as birdhouses or candle holders, starting with a clean gourd is essential to producing quality gourd craft projects. As gourds dry, a light layer of mold typically grows on their surface, a natural result of the lengthy drying time which usually takes several months. Your main goal during cleaning is to remove this mold completely. Although you can use an assortment of tools, all you really need to prepare your dried gourds for crafting is a butter knife, some bleach, a few kitchen cleaning supplies and a bit of elbow grease.
Ensure that the gourds are completely dried. Pick each gourd up and shake it to listen for the sound of dried seeds rattling inside. If you hear this rattling, your gourds have dried completely and are ready to be cleaned. According to the American Gourd Society, the seeds occasionally stick to the inside of the gourd during drying, in which case you won't be able to hear the seeds moving. (see reference 1) If this happens, tap the side of your gourd gently with your fingertip; if it sounds hollow, it is most likely completely dried.
Squirt a tsp. of liquid dish soap in a plastic dishpan and fill the tub with about 2 to 4 inches of warm water. Submerge your first gourd in the water completely to cover the entire surface with water. Let the gourd soak in the water for about 10 minutes. Bonnie Gibson, author of "Gourds," suggests that you cover the gourd with a wet dishcloth to keep the entire surface wet during the soaking time.
Rub the outside surface of the gourd with a metal scouring pad. Use short, brisk motions and press firmly to remove as much mold and surface dirt as you can. Pay special attention to the base of the stem and the stem itself, removing as much mold as you can from it.
Remove ingrained mold stains from the surface of the dried gourd. Grasping the butter knife firmly in your hand, use the back edge (the dull side) of the blade to scrape off the outermost layer of moldy skin in thin strips; the skin should come off easily since the gourd has been soaking in the water. Try not to press too firmly or else you may puncture the inner surface of the gourd.
Dispose of the dirty water in the dishpan and fill it with a bleach solution (one part bleach to 10 parts of water). Soak the gourd in the bleach water for 2 to 3 minutes to kill any remaining mold spores on the gourd's skin.
Rinse the gourd thoroughly and lay it out on a towel to air-dry completely before you begin decorating it. Repeat this process for each dried gourd you plan to decorate.