Well it is easy enough to make rope, by hand, on a small scale, out of cat hair, which is more woollen than human hair but seems more hairy than woolly. The trick is to tangle it up enough that it forms a conglomerate of tangles that can hold a rotational twist, at which point you can start folding it in upon itself to form a stable thread. It is, I expect, weaker than the sum of its parts, but much stronger than any individual parts, and you can keep scaling up its strength by halving its length… Now, yes, sure, you are going to want to find professionally-made rope if you can, you are not exactly going to hand-make many long-chain polymers out of your own skin cells, but if you just want something stronger and longer than any available materials and you possess the means to anchor the end points and mid point then you should be able to make string out of pretty much anything that can be tangled(bark would be difficult) and twisted(spaghetti would typically disintegrate). You just need to apply a consistent rotational force and then fold it in half, the two halves then twist into each other. The first time you have to be gentle because it is a mess of tangles, the second time it is basically string, but it is likely inconsistent(because being gentle lent itself to avoiding dealing with inconsistencies) so you need to watch out for weaknesses, but after that you have something pretty solid that you can halve more times if you want it stronger. I guess some sort of level would be needed to rotate it if you were doing it on a larger scale…
I imagine that you could do the same thing to light clothing and produce a less-efficient rope that would be more consistent than tying the cloths together but easier than teasing them into threads or braiding rags. Just cut them into long strips, bind them together(probably with needle-and-thread at pretty much random locations, but you could tie them together or something, glue might work but it would need to dry first…) twist them around until they hold a consistent counter-force to being twisted, then fold it in half, then repeat the twisting and folding steps until it is strong and consistent enough for your purposes… Of course, you can do the same thing with rope too but being cohesive rope would have a greater ability to slip…
