the skins = the dried inner tissue, just beneath the outer layer. the part with (supposedly) the highest alkaloid content.
i'm curious why you think he didn't get the full mescaline effect because i recently purchased some dried powder peruvian torch and was thinking of doing the same thing. i've never really heard anyone say anything about not getting all of the mescaline since you're ingesting it, i have heard it might take a little longer to kick in. this will be my first experience with any type of mescaline cactus so i was hoping to keep it simple like for my first time. i've done quite a bit of reading and stuff and i know about all the other methods/extractions but like i said being somewhat inexperienced i thought i'd keep it simple so if you know of a reason i should maybe not do this i'd be very interested to hear what you have to say. thanks