Soluble salts on a range of different cone 6 fired clay brown/tan bodies

The concentrations are not serious and are typical of what you might find on a commercial body.

Glossary	Sulfates Soluble sulfates in clay produce efflorescence, an unsightly scum that mars the fired surface of structural and functional ceramic products.
Glossary	Soluble Salts In ceramics, certain compounds in clays and glazes can dissolve into the water, then on drying these are left on the surface.
Glossary	Efflorescence A common problem with dry and fired ceramic. It is evident by the presence of a light or dark colored scum on the dry or fired surface.
Tests	Soluble Salts Evaluate and compare the solubles salts content in clay bodies and materials