During the Crisis of the Third Century, constant wars required a lot of coins to be produced, leading to heavy debasing of precious metal coinage. The antoninianus was eventually debased to the point where flans (blank metal disks) were produced with 5% silver or less, and pickled to dissolve the copper from the surface producing a spongy surface of almost pure silver. When these coins struck, the force of striking would produce a thin shiny layer of silver on the surface, which would quickly wear away. These "silvered" coins are not considered fourrées, since they are not actually plated since the metal is actually a continuous layer and these coins were not created to deceive.