Iron is the primary component of steel wool. Steel wool consists of bundles of extremely fine steel filaments, and ordinary steel is an iron-based alloy containing a small amount of carbon.
Manufacturers produce steel wool by drawing or shaving low-carbon steel into thin, sharp-edged strands. The resulting fibers are flexible enough to form a pad but abrasive enough to remove dirt, rust, old finishes, and small surface imperfections. Finer grades are commonly used for polishing and finishing, while coarser grades provide more aggressive abrasion.
Steel wool is often called iron wool or wire wool, but it is not made from pure iron. The small carbon content makes steel harder and stronger than pure iron, while the filament shape gives the material its characteristic scrubbing action.
A useful neighbouring fact is that steel wool can burn readily. Its enormous surface area lets oxygen reach the metal quickly, producing sparks and rapid oxidation. It should therefore be kept away from flames, batteries, and electrical short circuits.