Gah. The grease or not to grease debate. I picked up a Singer 5808c at a yard sale today. I never grab plastic fantastics, but the machine looks in great shape and with a little clean up could be a fast turn around for me. It feels like everything is moving smoothly but I will bet there are plastic gears inside. So Tri-flow grease? Good. I've got that. I've been wondering about the plastic gears too as some machines I've worked on have them and they do seem to be greased. I've seen the white grease too. Then in other cases I am not sure what to do, like my Bernina 730 where a nylon gear meshes with a metal gear. The old cracked gear had grease on it (the black kind) but I'm not sure what to do with the new replacement gear. ??