Tons of leftover shells accumulated around Muscatines cutting shops and button factories. In some instances, the finished button made up as little as ten percent of the original shell. Factories and cutting shops wondered what to do with the leftover shell and shell dust. Some began paving alleyways with cut shell and using it as fill. Button factories also collected shell dust. Many of the machines, such as the Double Automatic, had suction devises that trapped shell dust. Farmers had already discovered numerous applications for shell chips and dust, using it as a natural insecticide and grit for chickens.
A little experimenting led to the development of marketable byproducts. Muscatine native, George Gebhardt, saw potential in the leftover shell. His Universal Shell Company became a half-million dollar a year business. Gebhardts creative thinking, along with persistent marketing, turned waste into wealth. Gebhardt discovered that shell dust could be used as a mineral supplement for all types of animals. Gebhardt founded that dyed shell pieces looked attractive in the bottom of fishbowls and as decoration in flowerpots.
Muscatine also made more from mussel shell than billions of buttons. Ordinary items such as fishing lures, tableware, coin purses, candlesticks, and other novelties became treasured pieces when made from iridescent shell. Other shops turned shell parts, unusable for buttons, into jewelry and accessories. Companies in Muscatine worked with both freshwater mussel shell and ocean shell. Some companies became specialists in manufacturing belt buckles while others produced sequins, hat pins, tie tacks, and more.
As the pearl button industry declined in the 1950s and eventually ended in the 1960s, North American shell, particularly the washboard, became highly prized for use in cultured pearl production. Thousands of tons of freshwater mussel shell were sold to Japan for the cultured pearl industry. A tiny bead of shell, when implanted into oyster, transforms over one or two years into valuable pearl.