Is tin in coins

Many US cents minted during the period from 1864 to 1982 contained small amounts of tin. Even though most people call them "copper" pennies they were actually made of bronze, which is an alloy of copper with tin and/or zinc.

Depending on a number of factors, the Mint sometimes used just copper and zinc, or sometimes copper, tin, and zinc to make the bronze alloy. The copper content was always 95% but the proportions of tin and/or zinc in other 5% varied.