It probably depends on the detergent used, but the dishwasher can change the color of aluminum parts. I don't know if it's a chemical process that removes anodizing or just the abrasive action of some detergents. Dishwashers will do in silverplate flatware, too.
I like the idea of using diesel fuel oil as a solvent. Easy and neat disposal: strain out the crud and pour into the home heating oil tank!
David Bean
Arlington, MA USA
beandk at are-see-enn dot com