@Error @hotaru and I did ask ourselfs the question: how dirty fiber optic cables get and what it takes to make them clean again. So we made fibers dirty and cleaned them in various ways.
You can find the results at https://swagspace.org/blog/fiber-cleaner-tests/ as well as https://undefinedbehavior.de/blog/fiber-cleaner-tests/
(Both posts are the same +/- formatting).

Also here is a unicorn and @chuffchuff