Not all machines come as gunked up as my Singer 319. Iris, Hannah and I did clean up a 15 clone very quickly yesterday. That machine was totally stuck - nothing moved. It didn't have a huge layer of oil but it had some. It didn't have a lot of rust but it had some. We were able to un-stick the machine with just a drop or two of Tri-flow on all the moving parts. We started at the bottom of the machine and worked our way everywhere. I was amazed at how much a drop of Tri-flo could do. We took apart the bobbin area - it was really easy, cleaned up lint, cleaned gunk off and polished rust off chrome parts with chrome cleaner and barkeeper's friend. Then we reassembled that bobbin area. Then we took off the nose plate and cleaned it up. We just did one part at a time and had it done in a short time. There is some oil left on the machine but it will wait until a nice day in the spring.