yep.....that's OIL in there....
and it's ALL over everything, the inside of the receiver, the stock tube which was housing a fucking directly connected LiPo battery with no fuse or PCB, all over the motor, the piston, and inside the barrel.
One of the motor leads had broken in half and was soldered back together, there was also a break in the insulation of the wiring where it got crushed somewhere.
This gun is an ordeal, I have to take it to work and clean it all with degreaser, buy all new plastic parts, redo all the wiring, possibly a new motor, clean out the barrel and hopup chamber, and of course get rid of that LiPo since theres no protection of ANY kind on it.
Now this isn't the owner's fault, this is a hideous product of someone who didn't have the slightest clue as to what they were doing when they were upgrading this gun.
There's a reason systema packages and sells gear GREASE and not gear OIL.