To keep PMC moist, for the past ten years, I have returned it to its
packaging, wrapping it tightly in the clear plastic wrap first. When
it has been out of the packaging for any length of time over 5-10
minutes, I usually add a drop of water on the surface of the metal
clay and then seal it in the packaging. When its going to be stored
awhile after being opened, I moisten a small piece of paper towel
and place it in the package, outside the clear plastic wrap with the
Now there are small cases available, marketed, I believe, as PMC
Safes (just google it and I think it will pop up). They seal the
excess material while you're working. It's been suggested that
moistening and placing a small bit of the hydrating material that
florists use in the 'safe' helps to keep the metal clay hydrated.
BTW, there's a new book out, entitled PMC Decade, a gallery book
curated by Tim McCreight. I just received a copy and it's gorgeous.
Check it out.