To preserve decorative gourds, wash the gourds with soapy water, and rinse with clean, running water. Dip each gourd in diluted household bleach, or wipe the gourds down with the diluted bleach, and dry the gourds with a towel. Place the gourds on a flat surface in a warm location with ample ventilation, and allow them to dry for one to six months, or seeds inside the gourd rattle when the gourd is shaken.
To make a diluted chlorine bleach solution, mix 10 percent chlorine bleach and 90 percent water. If the gourds are too large to dip into the solution, dip a cloth in the solution, and wipe the gourds with the cloth. Do not allow the sides of the gourds to touch during the drying stage, and turn the gourds twice a week to ensure all sides dry evenly.
Place a fan in the room with the gourds to promote good air flow if the room has poor air circulation. After the gourds are dry, polish the outside of the gourd with sandpaper until it is smooth, if desired, and apply the diluted bleach solution to the gourds. Dry the gourds, and apply paint, stain or other decorations.