Jiraiya's forehead protector

[chaos4ever4]

he's a delinquent. he probably defaced the konaha symbol to his own amusement

[Neji-Aniki-sama]

Huh, since spoilers are allowed here, remember what he said to Tsunande???? I think he is more of a Shikamaru type, doesn't want trouble, but will get the job done if needed.
And he does go to a lot of trouble to train Naruto.

[Gods_Son]

I don't think we're supposed to read too much into it. I'd have to agree with lionheart on this one and say the only significance of the oil would probably be sticky fingers or somethin like that.