To perform a patch test, choose a Formula that you wish to use. Then wash a small area on the inside of your arm and wipe it clean. It’s best to choose a time when you have just taken a shower so you won’t have to wet this area again for some time. Apply a small amount of the cosmetic product using a clean spatula or dry table knife. Cover the area with a water-proof adhesive bandage that has an adhesive edge all around the area, not just at the sides. If the band-aid peels off, the process will have to be repeated. You should allow 24-hours and then carefully peel off the adhesive. If there is any redness, itching, or a rash, even a simple pimple, it indicates that you are allergic to something in this particular product. To be absolutely sure, clean the area again and apply an amount of the sample product. Cover it with new tape and wait 24-hours. If the reaction persists, DO NOT use the product.