In A.C., yellow caps were found on only some of the Caesars $40 strikes ... and had no special significance. Most of Caesars $40's came in clear caps, others in yellow on a random basis as far as I can tell. Many of the Caesars yellow caps were substitued to clear caps by collectors and players for the sake of better clarity, including myself. I remember selling or trading most of my empty yellow caps to a New York collector, Milt Sculky, several years ago. I don't have a single yellow cap strike from A.C. left.