During that time, Viking was using s different type of lubricant. And it was great for about 30 years and then started to harden up. Usually have have to heat it up to soften and clean every bit out, then oil it like regular.
it's not like cleaning up most machines, and there are a lot of non-metal parts so if they are stuck together and you try to force them - it goes "snap" and that is that -so Don't try to force anything, just keep cleaing and heating and cleaning and heating . . . and if you leave it sit and it hardens back up, then you didn't get it clean enough.
I'd also suggest not tackling one of these as your first vintage machine. They have a lot of moving parts that need to work together. Also join the vintage Viking yahoo group and read a lot before you start - or chances are you'll break something without even realizing you are doing it.
I've never been good at keeping count of my machines - I have quite a few that are fixable, but I already have ones like them so they will never be for the collection, and I have some I don't really want to keep for the collection - and those newer that I use but aren't to be part of the collection.
But it's easy now - I just say "over 100" and no one has ever asked me exactly how many over 100 I have LOL!!