I had a large lump (probably 30-35 grams) of copper clay left over from my first time using it. I stored the clay in plastic wrap, followed by two zip seal bags with a moist paper towel (to provide a little humidity). The outer layer of the clay was pretty dry. I decided the night before that I was going to use it the following day, so I opened it up and sprayed it with some water, wrapped it back up and let it sit overnight. I am glad I did this because it was softer the next day. However it was still so difficult to work with and I vowed that in the future I would never open a package of clay, without intending to use all of it up. When purchasing clay, it is helpful to consider that It may be a better value to purchase the larger package of clay, but the second you open the package, the clay begins to dry out and becomes harder and harder to work with as time goes by - at least in the dry desert climate that I live in.
Lesson 1: I will never open a package of metal clay, without intending to use it all up in one sitting.
Lesson 2: The longer the clay is exposed to air and the more you work with it, the harder it is to get it to do anything.
Back to the copper clay - I kept attempting to roll it out, shape or make "snakes" with it. I couldn't get it to do anything. It was very frustraiting and I kept asking myself why I invested so much money into this new hobby of mine. I could also feel small pieces of very hard and dry clay in with the moist clay. I hope those dry pieces won't be a problem during the firing process. After 20 minutes or so, I finally gave up attempting to make anything decent from the wet clay, and formed these lumps, that I hoped I would be able to shape when dry. Or if nothing better, I thought they would make a good test run in my new kiln.