Hi, I have a Socony Mobil Oil Co Grease for aircraft can. I was wondering how (or if) I should clean it. I was also wondering how much this piece is worth and also the age of it.
Below Is a picture.

http://s1234.photobucket.com/user/IAmAries/media/Antiques/image_zps3c09a9c7.jpg.html?sort=3&o=0

Thank You