These did not arrive in great condition. The delivery box wasn't damaged so I have to assume it's a manufacturing flaw. A couple of them were slightly misshapen. They recommend cleaning these with paint thinner, but DO NOT USE MUCH! I used ¼ strength, mixed with lukewarm water, and one of them was so deformed when it came out that I'll definitely NOT be able to use it again. I let mine sit for maybe 5 minutes, as well. I obviously should have just scrubbed them. Also, make sure after you get the craft resin off, wash them THOROUGHLY with soap.