Cock Metal
In 1864 H. Syer Cummings showed items made of Cock-metal at a meeting of The British Archaeological Association, and said he believed their manufacture commenced during the previous year. Cock-metal was there described as two parts copper and one part lead, but is copper 88%, zinc 2%, tin 10% on the Parys Mining web site.
The 1864 reference was probably just intended to indicate they were using poor quality materials. Analysis of several “brass” examples has failed to find any lead.