Abraum salts is the name given to a mixed deposit of salts, including halite (sodium chloride), carnallite, and kieserite (magnesium sulfate), found in association with rock salt at Aschersleben-Staßfurt in Germany. The term comes from the German Abraum-salze, "salts to be removed."
Abraum, which is red, is used to darken mahogany.
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Abraum salts". Encyclopædia Britannica 1 (11th ed.). Cambridge University Press. p. 72