Blueing was the laundry whitener that every household kept to take the yellow out of white cloth, sold as small hard balls, as a liquid, or as the blue dye called bluestone or anil. In hoodoo it became a bath and wash material used to 'clear' a person or a house - the logic being the one the laundry already had, that blue takes out what dulls white - and Hyatt's informants describe blueing balls in baths for cleansing and for making a person 'come out clean'. It is one of the clearest examples of a household article acquiring a magical use because of what it did to cloth.
A blueing ball is dissolved in the bath water, or in the water used to scrub a floor, usually together with salt or a herb preparation; the bath is taken for a run of bad luck or after a crossing, and the water is disposed of away from the house. In some accounts the ball is carried rather than dissolved, and in others the blue is added to a wash that is meant to make a business 'come clean' to its customers.
Blueing balls are a good corrective to the idea that hoodoo is made of exotic ingredients: the tradition worked with what a poor household had, and a laundry additive was as available as a root. The commercial successors - 'blue water' sold for spiritual baths - are a twentieth-century repackaging, and the corpus marks the household article and the product as different things.
Every entry that names Blueing Balls, grouped by the system it comes from.