Graphite Lubrication kit
Trapped key interlocks should be periodically lubricated with a small amount of dry powdered graphite. Do not use oil of any type as the oil will collect dirt and "gum up" the lock cylinder so that it will not operate.
Kirk Key Interlock Company offers a Graphite Lubrication Kit complete with instructions for use. The powdered graphite is supplied in a plastic tube that can be "squeezed" to force a small amount of graphite into the lock cylinder. Work the key in and out and turn the key a few times in order to distribute the graphite inside the lock cylinder.
Apply a small amount of graphite to each lock cylinder as part of your regular maintenance program in order to keep your interlocks working smoothly.
For further technical information please refer to the product datasheet.