2016/03/11 How do I perform the "foil" test?

How do I perform the "foil" test? 
Cut three small pieces of aluminum foil about 4" x 8" each. Fold each piece over a rod that you will use to suspend the foil in the tank. A clothes hanger works well. Your cleaner should be filled with an ultrasonic cleaning solution, degassed, and brought up to normal operating temperature. Suspend the first "square" in the center of the tank and the other two a couple of inches from each end of the tank. Make sure that the tank is filled to the fill line, and turn on the ultrasonic for about ten minutes. Remove the foil and inspect: All three pieces of aluminum foil should be perforated and wrinkled to about the same degree.