What Joe said. That is what my manual says and having had them apart to work on I agree that they need oiled more than just when they are cleaned and serviced. I oil mine, let it sit for a few minutes, remove the needle and bobbin and run it "full throttle" for a couple of minutes to sling that oil every where. That keeps me from getting excess oil on my projects. I have a piece of folded fabric that I sew on again after I thread the machine to run out any excess oil that gets on the thread. I always put that fabric under the presser foot when I put the machine away.