How to sprout mung beans
Take a large glass jar (I use a kilner jar with lid removed). In advance, take a new J-cloth type kitchen cloth and wash it. When dry, cut off a square piece that's big enough to allow you to put it over the top of the jar and secure it with an elastic band, with some of the cloth hanging down over the sides.
Pour in about enough mung beans to cover the bottom of the jar (you'll learn to adjust to the amount you want as you get used to it). Cover the beans with water and soak overnight.
Next day, stand at the sink for the following steps. Drain and rinse the mung beans in a sieve, rinse the jar and return the beans to it. Now, cover the beans in the jar with some water. Hold the cloth over the top of the jar with your hand (without securing with the elastic band) and tip the jar upside down several times so that the water comes out of the jar through the cloth. Sometimes a vacuum forms, and the water won't come out, in which case just readjust the position of the cloth. It's very important that you empty out all the water though the cloth (leaving water in the jar causes the sprouts to rot) and that you don't wring out the cloth (this makes the atmosphere too dry for the sprouts and they go brown). Now secure the wet cloth on top of the jar with the elastic band. Leave the jar on the worktop (I think you're supposed to keep out of direct sunlight - works for me like that). Repeat this water/tipping process each day until the beans are sprouted to the length you desire.
The beans take about 2-3 days to sprout. When sprouted, put sprouts in a colander and rinse. Lay on a clean tea towel and pat dry, then put in an air tight container and keep in the fridge for about 3-4 days. If they still look healthy (i.e. not brown), they are fine to eat.
If you want to have a constant supply of sprouts, you can keep 2 jars on the go, starting the procedure with the second jar a couple of days later.
Enjoy your sprouts!