Used motor oil that has impurities and dirt is fed into a centrifuge. The centrifuge carries a rotor that spins an extremely high RPM (revolutions each and every minute) and yes it pushes the impurities towards the wall in the container that houses the rotor. This works because the mass in the impurities is greater than the mass of the oil particles. Appropriate extraction methods are widely-used in order that impurities as well as the clean motor oil are properly separated, and also the oil is ready to be re-used. These filtering systems are also right for use with small-scale biofuel setups to remove any impurities. As of today, prevention is still, as it was before, loads better than cure. Tribulus is a great circulatory tonic; increases energy and can help build muscle and strength, as well as reduce muscle recovery time. It's a favorite of Olympic athletes and is great all round herb The best way to prevent this from happening is to re-think your views about it