Allergen Spray Concentrate Refill 2 Pack by Allergy Defender. Just add water: Add tap water to the top of the bottle. How to use: Spray in the air and on most surfaces. Use on pet bedding, couches, bedding, pillows, curtains, floors, walls and more. Do not use on water sensitive materials, silks, leathers, unfinished wood. Always colorfast test in an inconspicuous place. How it works: the minerals surround the non-living allergens, neutralizing and dropping them to the ground where they are dehydrated. How often should you spray the product? As often as needed. When spraying, step away to allow the minerals to work for up to 15 minutes as it neutralizes the allergens.