Pitchers are pottery

Pottery

Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...

 that has been broken in the course of manufacture. Biscuit pitchers are crushed, ground and re-used, either as a low-percentage addition to the virgin raw materials on the same factory or elsewhere. The crushed material is also used in other industries as an inert filler. Because of the adhering glaze, glazed pitchers find less use. The milled pitchers may be used as grog

Grog (clay)

Grog, also known as firesand and chamotte, is a ceramic raw material. It has high percentage of silica and alumina. It can be produced by firing selected fire clays to high temperature before grinding and screening to specific particle sizes. It can also be produced from pitchers...

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Archaeologists call ancient pitchers sherd

Sherd

In archaeology, a sherd is commonly a historic or prehistoric fragment of pottery, although the term is occasionally used to refer to fragments of stone and glass vessels as well....

s, or ostracon

Ostracon

An ostracon is a piece of pottery , usually broken off from a vase or other earthenware vessel. In archaeology, ostraca may contain scratched-in words or other forms of writing which may give clues as to the time when the piece was in use...

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