For the assembly line at Trek, we had bulk bearing greasers for bottom bracket and headset bearing retainers. The retainers were slipped over a steel rod, a pipe fitted over the retainers and rod, threaded fittings plugged both ends of the pipe, and grease was pumped into the pipe via a Zerk fitting. Once greased, the rod with all the retainers was positioned by the appropriate assembly station, and the assembler just picked nicely greased retainers off the rod.