Where Does This Carb Piece Go?

Due to unexpected circumstances, my car wound up parked in my garage for several years. Needless to say, the old gas really screwed my carb. It is a Edelbrock 1405. I have never rebuilt a carb before. I ordered the rebuild kit. I removed the carb and took it apart. I then submersed the pieces in Lacquer thinner. I then did some detailed cleaning of all of the surfaces and replaced all of the gaskets. I followed the instructions included in the rebuild kit and put it all back together again. I went to dump the Lacquer thinner and heard a small piece of metal rolling around in the container. This piece was not pictured in the exploded view diagram included in the rebuild kit and I have no idea where it came from. I have not installed the carb yet. Any ideas where this belongs?