I would NOT sand it, that will ruin it. You could use emory paper and that will make it sort of better and uniform with less damage, but I would not do that as my first choice. I would try woody wax, there is a kit with steel wool and 2 bottles, one is a cleaner, the other the wax. It works well and I've seen it bring back pitted metal to a decent look, it will never look like new but will look a ton better, and then if you continue to use it it will stay in good shape and not get worse. I switched to woody wax on my boat this year, but my metal work was in good shape, but it still beeds after 8 months in the water and looks the best it ever has, and woody wax is easy to apply and use, sure beats some of the other products out there. Alumiguard and other products really just protect the metal but do not bring back damaged metal, that is why they were not effective. I would give woody wax a shot honestly, if it doesnt bring it back, likely it is too gone and will need to be powder coated to protect it and give it a nice clean look.
