If you take it to a truck wash center, ask for it to be washed with the aluminum brightener. Majority of them use a product called Alumi-brite. When you have one acid washed it will eventually strip the finish off and in due time will cause it to chalk. Basically you'll have to acid wash it from then on unless you put a sealer back on. Just like an aluminum trim chute, in time you have to wrap the head gate or it otherwise leaves aluminum dust on there necks. I have mine and the schools trailer done where we take our trucks and they charge around $60.00 to do the inside and out. Just a thought.