"This isn't your mom's aluminum foil! Okay, wait it might be. Literally!"

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This mineral is a salt of boric acid. Borate is often added to cellulose, cotton, and other natural insulation materials, as well as some wood products, to repel insects, mold, and mildew; in insulation, it also acts as a fire retardant. The additive is considered safe, unlike some more toxic treatments, and does not impact air quality. However, Borate-treated wood is water-soluble and therefore is not an ideal choice for buildings exposed to a lot of moisture, although several companies are making strides to improve the product.