Here is some more info about the drums that I have.
When I was cleaning the drum on the outside I discovered a sort of stamp at the bottom.
Itīs not a very good picture but it says:Colvinsa (manufacturer in Colombia of barrels and such), 4(with dash above and under), Q-12-08.
Probably this barrel was made in December 2008.
Couple of days ago I opened de screw cap on top and shined with a small LED light in.
It indeed contained palm oil,there is a lil bit of white stuff left on the bottom.
Hmmmm...barrel+white stuff+Colombia......

The inside of the barrel doesn't seem to have a coating it looks quite blank.
If so,will a good cleaning with a degreaser work,wirebrush it after and clean it again?
The outside has a good paintjob on it and I really wanna contain it.