
The color of the yellow brick road first showed up as green in early Technicolor tests. It was adjusted so that it would read properly as yellow in the early 3-strip color process, which in 1938-39, was still in its experimental stage. The paint that was finally used on the bricks for the "Yellow Brick Road" was standard industrial yellow paint that was obtained from a hardware store several blocks away from the studio.
*****The cache you seek is micro. This isn't exactly a yellow brick road that you are following, but keep looking and you will eventually find it.
*****Congrats to LT Silverfox for FTF!!!*****