As a child I lived in the Canarsie area in Brooklyn. We played skully in the street with bottle caps that were filled with melted crayons or candle wax. Some of the fillers in the bottle caps were so cool, we wouldn’t even play with them. Started a collection. I used to put a penny in the bottom of the cap and then cover it with crayon and melt the crayon. It gave more weight to the cap, so it traveled a straight path. It was also helpful when we played games when “Blasties” were allowed, because when they hit the unweighted caps it would cause the lighter cap to go flying off the board. You could become a “killer” even before the other kid got back to the board. Sadly, I now live in Phoenix where it will be 116 degrees today and the ground is so hot it would melt the crayons in the caps…