Saggar atmosphere, or concentrate the effects of salts, metal oxides and other materials on the surface of their ware. Some pots may be carefully prepared for saggar firing. One method creates a smooth surface covered with clay slip, terra sigillata, which responds particularly well to the saggar technique. This slip covering may be burnished to achieve a gloss. Prepared pots are nestled into saggars filled with beds of combustible materials, such as sawdust, less combustible organic materials, salts and metals. These materials ignite or fume during firing, leaving the pot buried in layers of fine ash. Ware produced in filled saggars
Saggar glazed and again placed in saggars prior to being glost fired. Ware may then be decorated, and placed on refractory "bats" and fired again such as in a muffle kiln. A "Saggar Maker's Bottom Knocker" was a name considered sufficiently amusing for it to be featured on the television panel show What's My Line?. Whilst saggar making was a skilled craft, bottom knocking was far less skilled, consisting of beating clay into a metal ring. From the twentieth century studio potters have used saggars to create decorative ceramic pieces. In this use saggars are used to create a localised reducing