Unglazed pots have the advantage of holding a lot of moisture because they are porous.
Ceramic tile is sold in both glazed and unglazed varieties.
The type generally known to them is exceedingly light ware, for the most part made of light grey, unglazed clay, and having hand-modelled decoration in relief.
These toxins may become free in the culture fluid, and the living bacteria may then be got rid of by filtering the fluid through a filter of unglazed porcelain, whose pores are sufficiently small to retain them.
This group of vessels comprises black iron glazed wares on a bright red fabric, lead glazed wares on a bright red fabric, lead glazed brown wares and unglazed light red wares.