Originally Posted by poisonidea

There's a much greater concentration of oxygen in water than in air, in fact it's 1/3 oxygen, thats why things rust quicker when they're wet. The oxygen atoms in the H2O molecules bond with the iron in the steel creating iron oxide (rust) and small amounts of hydrogen gas, so theres no advantage of exposing the steel wool to air. Doesn't matter if the water's distilled or boiled it still contains the same amount of oxygen to react with the iron in the steel.