advice needed

some miserable bastard a very dear friend of mine on the gold coast recently sent me something in the mail that i can't believe made it past homeland security i am at a loss as to what to do with.

from the smell, i initially thought "dead wombat", but it appeared to be something rather more sinister than even that. it came in the kind of overly cheerful package generally reserved for suppositories and head cheese; and when i cracked it open it appeared to be filled with a goopy, black, tar like substance.

so far, though, its proven to be quite useful! i've managed to waterproof my boots with it, winterize my tires, touch up the grout between the kitchen tiles and substitute it for toad's blood in a curse i am levelling on my neighbour fix the rip in my pvc raincoat.

there is just one thing i don't quite understand: as i read the package for usage instructions and first aid warnings i notice that it says "41kj per 5 gm serving".

any idea what that might mean??? what IS this crap anyway???