I haven't seen this done on here although I'm sure someone must have thought of it. But, in the interest of making the silver on your Jango boots easy...
I bought this Permanent metallic silver marker at Michaels. It took minutes to apply and didn't require that I tape off the area because the tip is actually fairly sharp and outlines the area easily without bleed over. Then I just filled in the gap with the marker.
The flash has washed out some of the shine but they look great.
I think it looks comparable to the Rub n' Buff method with none of the hassle.
Hope this helps someone.