As of today, prevention is still, as it was before, loads better than cure. Used motor oil which has impurities and dirt is fed right into a centrifuge. The centrifuge carries a rotor that spins an incredibly high RPM (revolutions each minute) and it pushes the impurities to the wall in the container that houses the rotor. This works because the mass from the impurities is more than the mass with the oil particles. Appropriate extraction methods are used to ensure that impurities along with the clean motor oil are properly separated, and the oil is able to be re-used. These filtering systems can also be suitable for use with small-scale biofuel setups to get rid of any impurities. The third whorl of your flower is the stamen, your reproductive part. The stamen is made of a thin vertical thread-like structure called a filament topped having a circular or oblong structure called an anther. The anther produces pollen, which could be the male contribution to the reproduction process in plants.