As stated above do that with the oil. As for losing power most the time pulling it apart and cleaning the plastic fins and all the old grease out dose wonders. And if you own a IR2135 or any model of that sort if the trigger starts to act up, remove the inlet for the air gun its self from the 2 holes in the handle. Then check the little cog that the trigger needle pushes for air to allow air to operate the gun. Every impact gun maker is different so they are not all easy to break down for a good thorough cleaning / inspection. Since im a auto mechanics by trade I do mine about once a month, cause I beat on them and I need them to last as long as they can.