While the callused and fly-blown specimens are probably fine for a brew, prudence would suggest that the rotten specimens ought to be reserved for extraction (and sometimes they are remarkably potent- anecdotally at least).
I'd go so far as to suggest that you can probably just mash up the mushy cactus with some lime and pull it with ethyl acetate for rapid results. Adding powdered citric acid to the solvent pulls should give a pretty swift indication of the value of even a smaller portion of the mush if you choose not to commit fully at first.
And you can use other solvents but they mostly don't quite have that direct-to-crystals convenience of the EA.
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli