Which household items can lubricate metal best?

Water acts as a good lubricate but the disadvantage is that it can cause steel to rust and can evaporate quickly. Vegatable Oil is a good lubricant. As an alternative, melted butter. Graphite (aka lead) of a pencil is a good lubricant for certain applications. This is used in locks (such as on your door) to lubricate the tumblers.