The Greek head was carved in clay and cast in plaster. We broke some strands of hair removing it so I finished it with a stone effect paint to detract from the damage.
The Chinese Dragon was carved in air-dry clay and painted to finish because we were having difficulty with the casting methods. You can get hardeners to protect air-dry clay although I never did and lost a few pieces over the years because it becomes quite fragile.
I never owned a kiln (although we did look into it ) and was unable to cast the last head at the time which is why it eventually got sacrificed (it started to go mouldy under its cover). I also gave some air-dry pieces away as gifts (usually Fengshui dragons for good luck) but then stopped using clay altogether as I wanted to pursue stone, being advised to travel through wood first since stone can be extremely difficult.
I'm determined to get to wood at some point but currently have very little ability even to search for broken bits in the woods since I don't drive. But I will get there all in good time