I had this same issue with some Esso cans. There was 12, and I wiped the top of each one good..
next week, oil on top.. then again wiped it down..
week later, oil again on top.

Mind you they were all sitting straight up, and not moved. Same temperature, etc.

I stuffed a paper towel in each one, and on the top (previous owner had a big hole to get in) Mostly fixed the problem..