Last weekend I cleaned calabash gourds on my porch:
The calabash tree is a highly useful species. I first discovered it when reading The Swiss Family Robinson as a child. Rather like the gourds used in crafting, the fruit has a hard, wooden shell that is quite strong and useful for crafts, baskets, bowls and musical instruments, like this calabash-backed dulcimer I built:
You can bleach the interior of the gourds if you like. I have also heard of a bleach and lemon juice mix that is supposed to make them very nice, but I don’t have any specifics on that.
I just let them dry, then use them. These two are destined to be hanging lights.