Hi Heather:
In our family we use Ecover dishwasher tablets and an Earth Friendly Product called Wave Jet. What about running it without dishes with these products, to clean it? Also vinegar and water with a little baking soda (and some elbow grease ;)) works wonders.
Consumer Reports recently rated cleaning agents (green and not) for dishwashers; Bio Kleen was number one with Ecover tabs a close second...
hope this helps and good luck
b