If you are using tubes then you will have old tubes to cut up into rings to make big elastic bands. These were used for all sorts of things in the old days - from cinching your leggings from flapping before velcro or nylon webbing to holding your trials number onto the bike and sandwiches on the back of your seat. All my wet weather kit is rolled and stashed with cut up inner tubes, and has been for the last nearly 30 years and approaching 200,000 miles. Inner tubes will hold another tube well, with little risk of abrasion or coming loose - they have lots of friction. You can also loop them together to make a long strap to make like a large temporary bungee cord. I think it is a good idea to rotate these spare tubes too. Relying on the tube that has been folded up and fixed to a bike somewhere for the last 5 years is not a guarantee of getting home tonight. The spare tube goes on with a new tyre, the new tube goes into back-up. I think it's 3 punctures in the last 30 years, and only one more before that, 1966, I think.