I google searched it and found out you can use Marvel Mystery Oil to un-stick a tractor engine (they also said to use diet coke... so consider the source....) I bet it would work for unsticking 3 in 1 oil - they were also suggesting Kroil. Kroil is a good one if you can find some. I just don't know if it would have to be cleaned off after that and what would you use? It also looked like it was used to clean the old carburetors with lead gas... I also saw that you can mix it with kerosene to clean... that all said I didn't see anything about using it on sewing machines.