Which items should NOT be washed in the GSC470 dishwasher?

Iron, pewter, tin, and wood items should not be washed in the dishwasher, as they will rust, tarnish, or warp and crack. Non-dishware items such as electronic air cleaner filters, furnace filters, and paint brushes must also never be placed in the dishwasher, as they can damage it and cause discoloration or staining. Plastic items not marked 'dishwasher safe' should be tested or avoided. (Page 10)