Many guns come from the manufacturer in bad shape with regards to internal over greasing and dirt. Nothing that may not be solved with silk cloth and cleaning rod. Problems start once the gun can not work properly after overall cleaning process. Many manufacturers declare inside their relation to warranty, that any interference using the guns original state can cause your warranty annulment. Being responsible and doing a bit of research on disassembly process (manufacturers info ought to be the starting point) is priority, every incompetent handling with the gun can bring about permanent damage and cancelled warranty means no refund, right? If you aren't certain of the way to handle the disassembly and cleaning process, always employ specialized services. 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.