I recently purchased a used double guncase from the UK. It came with one side of the case packed full of fotter twine or bailing twine depending on what you would want to call it.

I couldn't figure out why the twine was in the case. Then I found a cleaning rod with a jag on the end of the rod and the jag was covered/wrapped in the fotter/bailer twine. I can't imagine that the twine would be a good cleaning patch but that's what it was obviously being used for.

As I cleaned out the case I decided to keep the twine just in case it works and if hard times hit and I needed it.