This is the easiest, cheapest and most rewarding part. This bike had been imported from Canada in the mid-1970's. I bought it for my son in the mid-1990's. Now it was coming apart in 2014. Needless to say, it was more than a little filthy.
As you can see, this is a complicated frame. Lots of brackets, nooks and crannies, and lots of recesses filled with 40 year old Canadian mud and California/Mexican sand. The amazing discovery is that despite the moisture, and its obviously hard life, there was no corrosion. Just the very slightest bit of surface rust on the swing arm and up near the headstock (where a little tiny recess for some tools turned up). It cleaned up beautifully. After probably 20 hours of work with steel wool (not available in Mexico!) and wire brushes it is ready to go. Just prime and paint when the time is right.