Originally Posted by jccaclimber

1. For future reference, yarn and a vacuum cleaner is a good way to get something from Point A to Point B in a tube system. Compressed air works too, but the opposite way obviously. Use the yarn to pull string or something of more substance, until you can pull your wire.
2. Assuming some slack, and no access for tweezers, a toothpick and a dot of superglue can fish a wire out of a hole if it isn’t in too far or bound up.
3. Make sure that wire isn’t rubbing on the BB spindle. On bikes with a shift cable there the cable goes over the spindle rather than under. Likely less important with a slack wire than with a tensioned cable, but you don’t want to run through the wire over time.