This is a cut through an eight-month-old slug of pugged clay. The cut was done near the surface. The patchy coloration is a by-product of the aging process. If a slice of this was fired in a kiln, an even and homogeneous white surface would emerge, with no hint of what you see here. A few moments of wedging will mix the matrix and ready it for wheel throwing or hand forming.
The process of mixing a plastic clay by hand before forming it. Similar to kneading of bread dough, it is considered an essential step by most potters.
Ceramic glazes and clay bodies can host micro organisms. They can be just a nuisance, a source of worry or they can render a product useless. What should you do?