I have slowly sold my collection of vintage sewing machines due to time constraints. I figured if I didn't spend a little time with each one oiling etc. every 6 months it might freeze up. I didn't use them to quilt and didn't want to be winding different bobbins for each machine. I still have a Singer-99, Pfaff 1222E, and a Bernina 1030. That's enough to keep going. How do you keep them all in top running shape?