The repairman was by this morning to replace the motor in our dishwasher. He suggested we use Tang every once in a while to keep it clean. Yeah, that Tang. THe powdered drink mix. He said it's the citric acid.

Kraft doesn't quite endorse the idea. But they don't discourage it:

We have heard that some consumers have used TANG® Drink Mix to clean their dishwashers. TANG® does contain citric acid which can act as cleaning agent.

TANG® Drink mix is intended to be a food product and Kraft Foods does not advocate its use for any other purpose.