Lost Reefing line inside boom

[GrumpyPawPaw]

Has anyone retrieved a reefing line from inside their boom? I was so happy to finally get the reefing lines set up, I forgot to put a stop knot in the end and it "disappeared" inside the boom at the gooseneck. Any ideas on how to get it out? It's a Kenyon boom.

[arf145]

I don't have a Kenyon, but when messing around with the reefing lines inside my Isomat boom, my plan if I were to lose a line was to push a line-fishing tape in from where I wanted it to go, out the other end where the line still was. Then tape the line to the fish tape and pull it back.