~65% Petroleum Distillates (Mineral oil)
~30% Stoddard Solvent (Paint Thinner)
~1% Tricresyl Phosphate (an organophophate, used as a plasticiser and solvent)
~1% Ortho Dichlorobenzene
<1% Para Dichlorobenzene
Personally, I think it smells great, but I don't think it's a magic elixir for engines. It's probably pretty safe for freeing up lifters if you don't add too much to the oil. A snort or three in the gas is fine, too, though I probably wouldn't use it on modern stuff.