Looks about right! Acetic acid wouldn't have yielded anything on evaporation by itself.
Quote: in a little while he will now if it worked or the spice remained in the initial caustic soup (that he threw away, argggg).
I once kept some base soup for about three years and eventually found that the residual occluded solvent had floated to the top and evaporated, leaving an appreciable quantity of crystals which could be purified by recrystallisation. So, yeah, never be too hasty with throwing your base soup away - at least if you have somewhere safe to store it.
Quote:he is wondering if 3 acid pulls(100ml each) where enough
300mL of 5% acetic acid should be ample to recover 500mg of base.
I hope your friend has enjoyed doing the extra bit of 'science'!

“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