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Any way you go about it, manually winding up a cassette tape is a long task. I estimate that 90-minute tapes take something like 1500 turns to wind from empty to full.

There is a certain very common tool that can aid in the process: a Bic pen. I'm talking about the ones with a clear, hexagonal body. A recent discovery of mine found that the gear holes in the cassette tape are 6-pointed, but more importantly, a Bic fits snugly into the holes. If you can't find one, try out a Biro or just a standard yellow pencil.

Because of the tight fit, the pen works just like an axle, allowing a whole bunch of uses. You can just crank the pen, but if you want a faster way, roll the pen between your hands or spin the cassette around the pen.

If you really went at it, you could do the thousands of turns in maybe 3 minutes. Just remember to spin the right way.

Helpful comments from other E2 users:

Master Villain reminds me that this might leave your tape loosely spooled. If you don't want that to happen, take the effort to find a mechanical rewinder.

If the fit is too loose, try holding the pen at an angle (P_I), or wrap some paper around the writing implement as a shim (SF).