Have been working with a pottery studio that does quite a bit of reduced-firing for special types of glazes. The clays that require low-oxygen to be fired can

Have been working with a pottery studio that does quite a bit of reduced-firing for special types of glazes. The clays that require low-oxygen to be fired can be embedded in special types of activated charcoal & reducing agents within the kiln. We've had some excellent results with bronze, have yet to try iron & steel. The firing instructions on those clays are similar to the bronze, however.