Well, this is really quite simple, and I do not understand that I have come up with this before.
1. Take one sheet of moss rubber.
2. Cut to fit with the die.
3. Run it through your cutting machine. (I`m using cuttlebug) (same discs with regular sheets)
4. Carefully peel off the excess material.
5. Stick it to an acrylic block.
.... and you are now ready to use your new stamp =)
This can be gently be washed with mild soap and water
Here is an example, I have used a dise from Marianne Design and one from Magnolia.