After changing a couple octaves of gut strings lately, I had an idea for re-purposing the small plastic zip bags in which the strings come.
I use them for jewelry when traveling, as you do. Also good for packing bars of special soap, or anything else that might leak, for trips.
When I change strings each year, I save the old strings that can still be used. I put them in those bags for future emergency use on lever harps (labeled, of course).
I also use the bags to organize rubber bands, batteries that may still have some charge in them, and twist ties in the kitchen drawer.
I use them for odds and ends in my string bag, such as my felt picks, ear plugs, etc.