The Greek language has contributed "maltha," to melt; the German "schmeltz," the old.    From Wordnik.com.  [Arts and Crafts in the Middle Ages A Description of Mediaeval Workmanship in Several of the Departments of Applied Art, Together with Some Account of Special Artisans in the Early Renaissance] Reference

Thus they form a heterogeneous assemblage of liquid hydrocarbons, of which naphtha and maltha may be said to form the extremes, and which have little in common, except their undefinable name.    From Wordnik.com.  [Scientific American Supplement, No. 362, December 9, 1882] Reference