Some machines are self lubricating which means the gears are embedded with silicone that lubircates when moving. A machine that is self lubricating should be run every so often, not put in a closet and forgot about. All machines need a little machine oil is certain places. Only oil labeled sewing machine oil should be used. It is made to evaporate so it won't get all gummed up in the machine. That's why the machine has to be oiled regularly, the oil evaporates. If the oil has a yellow tint it is not good machine oil. It should be clear.