Mint-made errors 5 centavos. Foreign coins struck on a U.S coin planchet or vice versa are very uncommon and hold a high value. Authentic error coins should not be confused with coins that are damaged after being minted, which is known as post-mint damage (PMD) or post-strike damage (PSD). Mints purchase long strips of metal which are fed through blanking machines that punch out disks known as blank planchets (or simply as planchets or blanks) on which coins are struck. This determines the size and shape of eventual coins. The punched disks are first known as "type-1 blanks (or planchets)". The disks
Metal clay used by artists more often than the gold and silver metal clays in the American market place. The actual creation time of a bronze or copper piece is also far greater than that of its silver counterpart. Base metal clays, such as bronze, copper, and steel metal clays are best fired in the absence of oxygen to eliminate the oxidation of the metal by atmospheric oxygen. A means to accomplish this –- to place the pieces in activated carbon inside a container – was developed by Bill Struve. Metal clays are also available as dry powders to which water is