Face-off: get the cleanest dishes.(up front: News / Trends / Advice)(Product/service evaluation)

Cleaning dirty dishes is big business, with Americans spending more than $500 million a year on powders, gels, tablets, and gel pacs for their dishwashers. Among the 20 detergents we tested this time, there was a wide range of scores, with some brand-name gels pulling low marks. That may be because most of the gels did not contain enzymes, which CR's research has found gets the grime out. (See "Dish Detergents," March 2005, page 39.)

Those enzymes are complex proteins that help break up food on cups and plates for easier removal. Often they are used in combination with other cleaning agents such as phosphates.

To test the latest batch of dishwasher detergents, a buffet of 17 foods-such as chocolate pudding, freeze-dried coffee, and green pea soup-was whipped up in a blender, left overnight, and baked in a microwave oven to harden on 10 dinner plates.

Nine of the tested products turned out to be excellent in cleaning the food off the plates, and most of those helped prevent soiling of other dishes and utensils in the wash. Other notable results:

Saving money. Three detergents were CR Best Buys, with costs of just over 10 cents per use. Two other top-rated brands cost twice as much per load.

Greener choices. Three of the products that say they contain no chlorine or phosphates-Ecover tablets, Method Dish Cubes, and Trader Joe's powder-were very good to excellent in quality. They also contained enzymes.

Taking care. Some of the detergents were harsh on silver utensils. Play it safe by washing silver by hand. Do the same for crystal and any glassware of sentimental importance, since etching can occur with repeated use and leave a cloudy haze on the glass.