P21S Vs. Collinite 850
I purchased both of these after a recent thread on metal polishes. I used these on a very neglected Combination Diamond Plate diesel fuel tank/tool box. This box had never been polished in 10 years. The P21S was used first and the easiest/cleanest of the two. The P21S did a fair job and removed some of the tarnish/oxidation and restored a fair shine. The Collinite 850 was up next and the black towel syndrome started at a drastic rate. As for the final gloss the Collinite 850 won hands down but took a lot more effort to get there. The solution I came up with was to use the P21S initially then use the Collinite for the added bling and protection. Be aware the diamond plate will start eating the P21S applicator. I did the top of the box by hand and when I moved to the front I used an Edge 8" green wool pad which turned black in a hurry. I tried spurring to clean it up but went no where in a hurry. I tried washing in Dawn which removed some of the black sludge, moved to APC then Mequiars Grease remover none of which worked. I then grabbed the Cleaner/Degreaser I bought at Costco that I pour into the washer with my micro fibers. I poured some on the pad and worked it in. That stuff is fantastic and took little effort to return the pad back to clean and green. At this point I wished I had taken some before pictures but I did take some of the aftermath.