Old Dupont #7 always seems to pop up in the final choices for cleaning chrome. It is a good polish, so is Turtle Wax chrome polish, another old name, but I think there are so many choices now that it seems to get put on the back shelf. I've learned a long time ago that cost and a high tech name are not very good determining factors in whether a product good or bad and old number 7 is cheap compared to a lot of other products. For aluminum, I think Mothers,(not cheap), is the best. So do the truckers.