I have had a wind up flashlight for a couple of years. Intended as backup lighting these are meant to provide about 30 minutes of lighting after a 5 minute cycle of winding.
Reality is 10 minutes of winding results in about 30 seconds of lighting. What holds the charge? Might there be a rechargeable battery inside which would warrant finding a way to open the case or is it some form of solid state capacitor which would mean just tossing the thing away?