What did you oil it with? First picture looks like solidified oil - almost like motor oil or something thick.
He used vegetable oil I believe, and yes I agree it looks like solidified oil residue. Perhaps the vege oil went rancid on the maille. That's one of the reasons I use inorganic compounds to prevent rust
A mix between olive oil and vegetable oil. I put a lot on, the whole hauberk is sticky but only some areas have the residue on them.
Sounds like an easy fix.
Ian, Aiden bought a can of clp, so I will use that in the future, or maybe use a different oil? If there is any that won't leave residue. I love the feeling of oily armor, and enjoy using oil, since it is what they did after all. Whether or not it was vegetable oil I don't know.