Every once and a while, you find a dusty, grimy time capsule of a bike. Found this small 1975 Mercian Professional in lovely lavender this weekend. It's is so wonderfully original and looks barely ridden.
http://picasaweb.google.com/
Poking and prodding a bit, I enjoy this kind of project as the rust on components appears surface only. The layer of grime is dry, caked. All rotating components are stiff as the grease has hardened. I guess that is natural preservative.
With careful cleaning and new grease, I think this bike will look as new.
John Siemsen
Portland, Oregon