First of all, it did remove stains on the tubing when applied as directed. It also did not appear to harm the anodized finish. (I also applied some to a piece of painted aluminum siding and nothing untoward occurred.) I cannot say how long the protective coating it leaves behind will last because I tested it just prior to deadline. Be sure to shake it well. And do apply from the bottom up as the directions state. (When I applied it from the top, the stuff that ran created streak "shadows.") It supposedly works better on wet aluminum, a feature pontooners will find convenient. It retails for $19.99 at boatbling.net.