will any harm come to said tracks? got spade ace Merkava IV tracks and painted them with Tamiya's dark iron. looks ok on plastic tracks, but not so good on metal. thought I'ld get some blacken it or these tracks. thx

Blacken-it will work on any metal track, but it's a bit hit-or-miss. The results are unpredictable. The oxidation process could turn a rusty brown to a dark, or light gray. I would suggest keeping an eye on the tracks and pull them out when they're the right color. Also, keep agitating the container with the solution to keep air bubbles from being trapped in track recesses. The solution will not affect the metal where there is an air bubble. If a whitish residue forms on the tracks it can be brushed off when dry. A light sanding over the raised detail will give the tracks the worn look. PS - won't work on painted track. Strip them first!

yeah, I was afraid of that, the paint. shoulda left as they were