These wonderful products actually cleanse the air that we breathe via the same basic process as those widely advertised synthetic ionizing machines. The difference is that these products look much better and cost much less. In a nutshell, when the salt is heated from a bulb or flame, it releases negative ions into the air. Most pollutants and allergens are positively charged ions. When the negative ions created by the salt enter the air, they bond with the positively charged ions of the pollutants and allergens, thereby neutralizing them.