Without access to reagents or chromatography,burn, melt and smell tests?
Retrieve via solvent, freeze precip or evap, yes? Then a mini a/b re-x?
EDIT: FASA would result in a salt precipitating, right? Then retrieval would be a mini a/b that would in effect clean and re-x? I have no experience with the FASA chemistry route.
Sine experientia nihil sufficienter sciri potest -Roger Bacon
*γνῶθι σεαυτόν*