Cosmoline is a generic name for that particular class of rust preventatives. It's not always mixed the same or applied on perfectly clean guns, so it can be affected by oils/greases that already on the gun, moisture, or the age of the application. It actually got it's name from the people (cosmoliners) who applied the stuff to the guns. So cosmoline or "cosmo" became a generic term for the preventative.....like calling all adhesive bandages Band-aids.
Anywho, I know that was a long explanation to tell you that it's not uncommon for cosmo to smell differently. I thought my last shipment smelled like an oil-well pump found out in the fields of midwestern states. My girlfriend thinks the same batch smells like a dude who hasn't washed his "junk" in over a month. One of my bosses loves it and rubes it on his neck like cologne.
