Well, tow things come to mind.

1. A little Castor never hurt anything.

2. Ask for a MSDS, the law requires that the fuel contents be explained for safety purposes in the MSDS for possible treatment and remediation. That is an OSHA requirement, it is the law. The fellow can be severly fined if he is selling this stuff and does no have an MSDS registered. If he is giving it away, well that's another matter.

Good luck,

Chip