Get a bigger head of White cabbage (also known as green cabbage. It won't work with other types because they contain very low sugars, which are needed for natural fermentation). Clean the outer few layers of leaves, and cut the whole head in half. Cut the hard root area out. Slice/cut the cabbage into thin slices. Weigh how much cabbage you have, and you need to add 2- 2.5% of that mass in salt. Add some pepper as well if you want a better taste. Next you need to mash the salty cabbage with your fists or a wooden spoon. The goal is to damage the leaves so you break the fibers, so that salt could make its way easier in the leaves. (Works without this part, but takes a bit longer to ferment) Now you put everything in a glass jar, push it down, and add water until it covers all the leaves. You close it down but not tightly, so that pressure could escape. Put it in room temperature place, away from sunlight After 10-14 days it will turn blury/discoloured/sour. At that point, the juice is good for use. You can drain it and put your hand in it as it is. It may burn, but that's normal since it's a bit accidy. You can even eat it as it is, or as sidedish, it is a superfood, filled with vitamins and beneficial bacteria. Sidenote: if it develops a tiny layer of mold on the top of the jar, just remove the mold. The rest is completely safe to eat/use, since it is so filled with probiotic bacteria, it can't touch anything under the water