nightmare.org
American Superstitions at nightmare.org

Superstition #1270

It is quite customary, both in the United States and in Canada, to give the whole house a thorough cleaning after a death has occurred, even when the deceased has undergone no prolonged illness and has died of no contagious disease. A day or two after the funeral one sometimes sees, particularly in country homes, feather beds, mattresses, etc., etc., put out to air. Sometimes even rooms are whitewashed in the purification process.

Source: Current Superstitions (1896), entry 1270.

Fanny D. Bergen, editor.