Illustration ST 02 shows, on the left-hand side, sieving and sorting. The gold prospector scoops up mud and stones from the shallow river-bed on a sieving-pan, and sieves the muddy suspension. When the water and mud have passed through, he hopes to be able to find shiny pieces of gold dust among the remaining gravel.

The right-hand side of the illustration illustrates the sorting method. In this case plastic bottles are being sorted according to the type of raw material from which they were made. It shows manual separation of PET and PVC bottles, which facilitates the re-use of these raw materials.

The pattern on the bottom of the bottle, as shown on the illustration, makes it easy to see which raw material the bottle is made from. Today, household rubbish is often sorted manually out of consideration for the environment.

The middle of the illustration shows the separation of a solid – solid mixture according to its magnetic properties. One of the components is magnetic and can be separated from the rest by a powerful magnet. In this way objects made of iron can be separated from household rubbish. In the same way magnetite, an iron ore, can be separated from the accompanying stones (gangue).