Clean the insoles with vinegar. Using a mixture of 2 parts vinegar and 1 part hot water, soak the insoles for a few hours. Vinegar is a natural disinfectant and will work to kill the bacteria hiding in the shoes.
Huge amounts of iron are used to make steel, an alloy of iron and carbon. Steel typically contains between 0.3% and 1.5% carbon, depending on the desired characteristics. The addition of other elements can give steel other useful properties.
However, its use only became widespread in the 14th century, when smelting furnaces (the forerunner of blast furnaces) began to replace forges. Iron ores are rocks from which metallic iron can be economically extracted. These rocks are usually found in the form of hematite (Fe2O3) or magnetite (Fe3O4). About 98% of world iron ore production is used to make iron in the form of steel.