[horsa]

The stuff I used converts the rust to a black oxide. The conversion was very fast. I tested first by dabbing a little onto a spot with a rag and it turned black almost instantly. That was enough for me to decide to dump the contents of the jug into a small bucket and to apply it with a very cheap 2" wide paint brush. If you slop it on enough to pool up, it does the conversion and the excess dries like latex caulk which can be peeled or scraped off without any affect to the metal that converted underneath. Less work to paint evenly but that takes a lot longer also. I started out being neat but as my paintbrush started to get clumpy from jabbing it into the holes in the links, I adopted the quick slopping method. The chemicals didn't eat the brush but the method of getting to all of the track surfaces pretty much killed the brush after doing all of one side for both tracks.