When used properly this product will turn your zinc black. Instructions are included on the bottle.
Chemical Tip - 1) Remove all oxidization with steel wool. 2) Clean surface with vinegar (this allows for a more uniform/dark color. 3) Rinse with water. 4) Wipe chemical on zinc with plastic handle brush, Q-tip, or paper towel. 5) Let patina sit on zinc for desired color tone. 6) Gently remove excess with a clean cloth. 7) Let chemical air dry hard