Shrinky Dinks were invented in 1973 by Kate Bloomberg and Betty Morris from Wisconsin. The first kits were manufactured by the major toy companies of the time such as Milton Bradley, Colorforms, Western Publishing and Skyline Toys. The shrink plastic is still available from many retailers and can be used for anything from charms to pins.
Prior to heating, the thin, flexible polystyrene plastic sheets can be coloured with felt-tip pens, colored pencils or crayons and cut into shapes. When heated in the oven or with a heat gun, the plastic shrinks by about 5/8ths and becomes thicker and more rigid, while retaining the colored design.
Although Shrinky Dinks is considered to be an arts and crafts product for children, many adult crafters find the product to be suitable for jewelery making and other projects.