Cleaning agents

Q: Do cleaning agents need to be kosher for Pesach?
A: No, since chametz which is inedible to a human being and a dog is not considered chametz. Therefore, cleaning agents are not chametz. We have the custom to use dish detergent which is kosher for Pesach. It is not necessary according to the basic Halachah, but we certainly do it anyway since it comes in contact with the dishes, utensils, pots and pans.