Aluminium, plastic and glass can be converted into pans, fleece clothing and windows if bottles and cans are not used to make new ones.

Recycling is good, waste is bad. Many people have learned this simple logic. But some types of recycling are better than others.

The best type is that Dansk Retursystem carries out, which is 1 to 1. Every empty bottle or can becomes nearly one new bottle or can because the material is high quality. This requires that the aluminium, glass and plastic from bottles and cans not be mixed with the aluminium, glass and plastic from other items so that it remains high enough quality for food packaging. In theory, this type of recycling can go on forever.

The next best is when bottles and cans are used for making other food packaging: for example, aluminium trays for pâté or plastic cartons for tomatoes. This is also good, but in Denmark we do not collect these types of packaging, so recycling only happens once and then the trays are discarded.

In third place, low-quality materials are recycled so that they cannot be used for food. Instead the materials can be used for other things such as plastic for garden chairs or fleece clothing, aluminium in a bicycle frame or a pan and glass for windows or light bulbs.

In last place come recycled materials that are mixed with other substances, and the quality is so poor that very few products can be made. Examples of this include aluminium in asphalt, plastic in carpets and glass in insulation foam.

All four types of recycling can include bottles and cans but only in one direction. A beer can may be converted into a new beer can, but a bicycle frame can never become a beer can. Instead, new raw materials must be mined and the process started from scratch, which strains the environment and adds to climate change.