External use:

Always use unboiled water. You may prepare enough clay for several days use. Discard clay after use.

Mixture
Use an enamel, wood, glass or earthenware container, do not use plastic or metal (except stainless steel). Mix 1/2 cup (125 mL) of clay in the container.
Keep some clay aside to thicken the mixture if necessary*.
Add unboiled water until it forms a firm paste. Let the mixture stand undisturbed for one hour. The resulting paste should be smooth, homogeneous, and thick enough that it will not flow.
*Begin by making a watery mix. It is easier to thicken than to thin the paste.

100% surfine green clay (montmorillonite).

Avoid using during pregnancy or nursing. Keep out of the reach of children.