After being cured, the hides can be stored for several months without rotting and can be shipped to manufacturers throughout the world. Cured hides arriving at a tannery are rehydrated, or resoaked, and washed in large, rotating wooden drums. After the feathers are removed, hides are delimed, or neutralized, with acids and treated with enzymes to remove any deposits and to increase softness. The next operation is called pickling. The hides are soaked in a solution of water, salt, and hydrochloric or sulfuric acid.
Tanning is the final process in turning hides and skins into finished leather.
Properly tanned leather can pass the test of being boiled in water for three minutes without shrinking. There are several methods of tanning, but the two most common are chrome and vegetable tanning. Chrome tanning is the most used. Most leather shoe uppers and garment, upholstery, and bag leathers are chrome-tanned. The process begins in rotating drums with a bath in a chemical containing trivalent chrome.