a man dropped 2 machines off and asked me to sell them if I didn't want them. they both sew beautiful and one is a singer 66. what do I use to clean it? was using dawn and hot water but alot of build up on it. not even sure what to ask for it because kind of sure I do not need it. the other machine is a wards and surely I do not think I will be able to get much out of it for him. any help with cleaning ideas and price would be greatly appreciated. thanks