Goof off is xylene, toluene, and benzene, if I remember correctly. I did my Summer's in a factory in college and practically had to bathe in the stuff to get some of the crap off me from the stuff they made me do.
It's supposed to be highly toxic and may eat through some plastics, but I haven't died of cancer yet.
North East Reloading had them at $125/500 without the tar:
M118 LR 175 Grain Sierra Matchking
Hopefully, I won't get in trouble for posting the link and I'm in no way affiliated with the seller. Haven't done business with him yet either.