8 New 18K Gold Testing Solutions. This is a new set of eight 18 karat gold testing solutions. Each bottle has 1/2 fl oz of acid. These are the finest acids made today. Sturdy plastic bottles maximize safety and allow the user to easily squeeze out one drop at a time. Due to testing acid being classified as a hazardous material it cannot be shipped by air and can only be shipped to the lower 48 states.