I would:
pull off his finger nails one by one, then goes his teeth, one by one. skin his head by each square inch. i wont touch his dick or balls but a hammer will. by hammer, i mean sledge hammer and put them on the table, then hit them continuously until flattened. then cut off each of his toes with a cigar cutter then i would run him through several razor blades, leaving him with deep cuts all over his body. then dip him in vinegar once he thinks that is bad bring on the acid, as in LSD cuz he would have the worst trip possible to mankind, it would fuck with his mind worse than it could be fucked with sober then. kill him once he's sober, by means of throwing him off a bridge, and a shovel and bag of lime will make sure hes never seen of again.