Jax Brown Darkener - Metal Finishing Solution - Antique Finish Without Heat or Electricity - 2 Ounce? If the metal is clean, the JAX Brown Darkener will work quickly. If left for too long the Brown Darkener will rub off the metal easily. Practice and experience will help you find the right timing for your work. If you are going to dip your metal into JAX Brown Darkener, you may want to dilute the JAX with water; this will slow the reaction down and allow you to have more control over the finish (there is no magic dilution ratio? a little experimentation will allow you to arrive at the optimum ratio for your work) Always use JAX Products in plastic or glass containers. When you dispose of used products and containers, please do so at an approved waste disposal facility. Never reuse an empty JAX container. Make sure to refer to the Safety Data Sheets for additional information before you begin. Do not mix JAX Products with any other chemicals.