For odd lengths of laid up line, I use "zip-loc" plastic sandwich bags. I coil the line loosely and place it in the bag along with a standard index card with a notation of the length of the line, the color, size, and material (by manufacturer's code numbers) and brand of the thread it was made of, and the description of the lay-up, e.g.: "LH (left hand) 1x3 (3 single threads)" or "LH (left hand) 2x3 (3 doubled threads.) I keep them flat, stacked in a box. An example of the total card information would be:
35" Gutermann Mara Polyester 120, Black #696, LH 1x3
If it's left-over line from a build, I will make a notation of that, as well, identifying which model and what lines it was used to depict on the model and, if I had "scaled" it at the time, I'll note that, too, e.g. Tern Schooner, halyards, 1:96 1.25 inch line."
I can go through my stack of plastic bags and find what I want without having to handle the line unless I'm going to use it.
When I use it up, I tape a short sample to the index card and save it in case I want the "recipe" to make more of the same stuff.