Sometimes called GI Grease has been around a (100 years). [I]'ve purchased many old military rifles over the years and many of them came packed in cosmoline. Its disgusting, smells,and is difficult ti excise from any firearm, mainly because it was applied by dunking the whole rifle in a vat of the stuff. However, I don't think it can be topped for protecting gunmetal and its blueing. Let me give you a good example; several years ago I applied to the gov't for 10 M1 rifles as replacements for our American Legion Springfield 1903's which were worn out. For just the cost of shipping and promise to return the 1903's I received 10 brand new WW2 era M1 rifles which were packed in cosmoline 60 years ago.It took several of our members over two weeks and a gallon of Hoppes to degunk these beauties, but it was worth the elbow grease(excuse the pun).