Plastic tub Liquid dish washing soap Old towel "Chore Girl" scrubber Non-abrasive scouring pad (I use Scotch-Brite Multi-Purpose, No-Scratch Scour Pads) Protective rubber gloves for your hands
The hardshell gourd comes from the field with mold covering its surface. Mold forms on the outside of the gourd's shell as a natural part of the curing process as moisture leaches from the interior of the gourd through the porous surface. This mold and other natural elements create the interesting markings on the exterior surface of the gourd. I personally like these markings and think they add character and natural texture to the surface, so I am careful to clean the gourd with a process that does not damage this surface. This means I avoid sanding and bleaching the surface.
The method I use is best done outside, for easy disposal of the dirty water. No toxic cleaners are used so there is no harm to the environment. The loosened flakes of mold will fall off into the water, however, and this is not debris you will want to pour down your sink.
First soak the gourd in a tub of warm soapy water for 30 minutes. The gourd is hollow inside and will float. To keep the entire surface moist, cover with a wet towel that has been dipped in the soapy water. The towel will both keep the gourd submerged and insure that the entire surface remains moist. Because the mold has dried by the time the gourd is cured, some of it will loosen from the surface and fall off in the soaking process. At other times, you may have bits of skin and mold that will be tough to remove.
Once the surface has soaked, scrub the gourd surface with one of your scrubbers, using the softest one first. For tougher to clean areas, use the non-abrasive scouring pad. The water will be very dirty by this time with lots of debris. When the gourd surface is as clean as you can get it in this first wash, change the water and repeat the soaking process.
This combination of soaking and scrubbing, will remove all the mold and debris from the gourd's outer surface. When the gourd dries you will have a smooth, natural and clean surface to cut for a basket or leave whole for applying art.