Printed circuit boards contain a large amount of precious metals like gold. This is because precious metals are very good conductors of electricity. There a number of methods that can be used to separate the gold from a circuit board. While scraping the gold from circuit boards can be the method that recovers the most gold, it can be time consuming and is not the most effective method. A chemical circuit board stripping solution is a much more effective method of separating the gold from a circuit board.
Put on safety glasses and rubber gloves; circuit board stripping solutions are very acidic and can damage eyes and skin if you don't use proper safety equipment.
Mix the circuit board stripping powder with water to make one gallon of solution. Follow the directions for your specific brand of circuit board stripping powder, as each type will require a different ratio of powder to water.
Place circuit boards into the solution. Soak the boards for six to eight hours.
Remove the circuit boards from the solution. Rinse off the circuit boards, making sure that you rinse off all of the gold flakes that have been separated from the board by the stripping solution.
Filter the rinsing water to recover the loose gold flakes. Dry the flakes and melt or refine them using any method of gold refinement.
You may need to separate the gold from a number of circuit boards to recover an amount of any value.
Wear your safety equipment at all times when working with the stripping solution.