- Cut a section of aluminium foil the length and depth of the ultrasonic tank.
- Immerse section of aluminium foil into the liquid in a vertical hold.
- The foil must not make contact with tank bottom and be left for a duration of 30 seconds.
- A consistent pattern of perforation should result with hole sizes varying from 1 to 4mm in diameter.
- Foil can be purchased from any supermarket.
In larger ultrasonic cleaners more than one section of foil may be immersed.
If the foil test is to be done at the beginning of the day, the fluid should be removed from the tank prior to the cleaning of instruments, as the solution left is foil contaminated.