Duncan's only string pack that contained a small disc of soft wax. You lightly rubbed the wax over the entire length of string or just to the string loop that went around the axle. Waxing cotton string was supposed to extend spin times and prolong string life.
It's interesting that no yo-yo manufacturer or yo-yo string maker has ever sold waxed yo-yo string, akin to waxed shoe laces that you can still buy today.
