Nickel in jewelry, watchbands, keys and other common metal objects can cause irritation and other issues. A 1/2oz shatterproof bottles, to protect from cross contamination, allows the user to easily squeeze out one drop at a time. ·Latex Gloves are recommended with the use of any testing acids for safety · place 2-3 drops on a cotton swab. Rub the moistened tip on the object for 5 seconds. If it contains nickel, the cotton will turn pink. Please be sure to test in an inconspicuous area, just in case the solution may discolor the metal.