Take one of the tuber ware containers remove the lid. Then cut a hole on the side by the bottom for the leo to get in. Turn it upside down and cover the whole container with plaster of Paris You may have to do this 2 or three time depending on your desired thickness. Do the same thing to the top. Once it's dried you can remove the plastic container and the cover. To paint it use a cup of alcohol the rubbing kind and India ink. Don't use too much ink just enough to color the water. Like a few drops. Brush it on and let it dry then repeat until you get the desired color. To add effects just brush some more on but not everywhere. This should dry in 10 minutes between coats. Once done put the top on and you’re done. Just let it sit for a day or so to let all the alcohol smell fade away. This will give you a gray color rock. You can also use acrylic paint with water but make sure you put very little paint as you want it very watery like the dirty water when you clean the bushes in a cup. The more coats the darker it will get just let it dry between coats. Hope this helps