Nah, no restrictions on sale. I reckon tell them you want to fill a computer with it. Vets are nice people, they deserve amusement wherever possible.
This is done reasonably often by people. Hard drives do not work under oil, or under any other non conductive fluid. There's an epic thread on this over at silent pc review. Apparently casting acrylic around a hard drive waterproofs it, but it does overheat.
Biggest problem is that oil wicks up the cables, so a little pool of oil accumulates under your mouse, monitor and so forth. Transporting is also harder, and changing components a bit more interesting. Lables mostly peel off. Fans work, for years, they just spin slowly.
I'm also reasonably tempted, but it would mean abandoning any hope of ever moving my computer which is more than I want to do. I think the best answer is the hybrid of watercool computer normally, run pipes to radbox full of air and fans, and submerge the motherboard in oil. I'll probably do this one day, but not right now.
