Trey, aluminum is such a “soft” metal. It is very hard to find something that won’t streak when you wash it. For a detergent to be brushless is usually will have a very high alkalinity (high PH 12 or more). This will streak or stain the aluminum. We finally stop trying to use anything on polished aluminum trailers that did not have a neutral or very close to neutral PH. We no only use Classic Brown and and brush. Customers are very happy and we don’t streak the trailers. We do use our regular truck wash soap V-505 or R-109 on the under carriage.
