The best waste is the one that never arises in the first place or that can be avoided. Nevertheless, every day many things are thrown as waste into waste paper baskets, dustbins and other refuse containers. Thus enormous amounts of waste are generated which on the one hand, accumulate,  and on the other hand, there are still a lot of valuable materials contained in the waste that can be further used. Moreover, raw materials such as oil, which is made into plastics, or ores, from which metals are obtained, are available only in limited amounts on earth.    In order to reduce the volume of the waste, which would otherwise be burnt in incinerator plants, and to reuse the raw materials, a law on waste management was passed in Germany already more than 20 years ago, which regulates how waste is to be reused in a sort of circular economy. Certain materials in the waste, such as paper, glass and metal, have been recycled since – that means they are separated from the waste, sorted and reused.   The word ‘recycling’ is derived from English and consists of the syllable ’re’ for  ‘back‘ and the word ’cycle‘ for ’circle‘. So in recycling valuable materials are to be brought back into a cycle.  An example of such a cycle is the hydrological cycle. Over large water areas, water evaporates due to the heat of the sun and thus clouds form in the atmosphere consisting of small droplets of water. These clouds travel over the land and, when it is raining, snowing or hailing, the water falls on the soil surface as precipitation. There it collects in rivulets, streams and rivers and ends up in lakes and the sea where the heat of the sun evaporates it again. So the cycle can start all over again. In recycling the idea of a cycle has been adopted. We start with the new product that can be purchased in a shop. The next step in recycling would be that the packaging or the product itself are thrown into the dustbin after use. At this point in the cycle, the materials must be differentiated and separated as much as possible, so that a cycle can be created in the first place.   Then the materials are transported to central collecting points, sorted again and cleaned – because the better a substance is separated from the rest of the waste, the better the cycle works for this substance. Eventually, the substance is processed in such a way that it can be made, as a new raw material, into a new product that can be bought in a shop. Thus the cycle of any recycled substance begins anew.