How To Store Clay Powder
Below we are going to give some recommendations on how to store both dry, as well as hydrated cosmetic clay powders.
It is recommended to store hydrated clay in an air-tight and non-metallic container such as ceramic, stone, or plastic.
Hydrated or liquid clay should be kept away from the elements, such as moisture, heat, and light.
You may choose to refrigerate your hydrated clay, and it will likely last longer if you do so.
Another recommendation is to only insert clean utensils into your hydrated clay powder. If you use your hands or unwashed utensils you can introduce bacteria into the material which may cause it sour at a faster rate. Some may refer to this as 'double-dipping'.
As hydrated clay is kept, it is common for the material become thicker as the water evaporates. If it dries out, you could try adding more water.
If your stored hydrated clay powder begins to smell 'off' then it has likely turned and would no longer be suitable for use.
Dry Clay Powder
Dry clay powder is relatively easy to store, but should also be kept away from the elements. (moisture, heat, light)
It is also recommended to keep clay powders away from anything with a strong scent or odor. It is possible for clay powders to pick up fragrance from it's surrounding environment. Most cosmetic clay powder has a natural earthy type aroma.