I live in ca and none are as good as they used to be. Truck shops that sell accessory's will be up on what still works the best. They took the zink out of the
oil also which caused some problems. No need to go into junk gas that we have to use in ca. Sometimes you see products at shows that work well, such as stuff I buy from fellow Prevost owner to polish stainless steel, big job on a bus. I have tried all products mentioned and the ones that turn your rag the blackest the quickest is what your looking for. Have not bought product out of state so I don't know if they would be old formula.