Two ways to prevent the rusting of iron are :

$(i)$ Oiling, greasing, or painting : By applying oil, grease, or paint, the surface becomes water proof and the moisture and oxygen present in the air cannot come into direct contact with iron. Hence, rusting is prevented.

$(ii)$ Galvanisation : An iron article is coated with a layer of zinc metal, which prevents the iron to come in contact with oxygen and moisture. Hence, rusting is prevented.