Oh this looks exactly like the machine I bought yesterday, it's stuck in our car til we get to move into our new home and I can't wait to clean it up. I'm not sure what model mine is because I can't open it up til I get it out of the car. There were a bunch of sphinx models from what I saw on the internet so it could be a 27/28 or 127/128 and I think there was even a 15 version.
These are the links to a great cleaning tutorial on this forum.
pt 1 - Disassembly -
http://www.quiltingboard.com/t-45816-1.htm
pt 2 - Cleaning -
http://www.quiltingboard.com/t-45983-1.htm
pt 3 - Finish Repair -
http://www.quiltingboard.com/t-46696-1.htm
Refinishing old sewing machine cabinets
http://www.quiltingboard.com/t-97670-1.htm