Excellent finding, Plaincoil.

SWIM just converted some of his brown acetate/carbonate mixture of ~400mg (SWIM actually forgot to weigh, beforehand) and converted to HCl.  It formed a very dark resin after evaporation, so SWIM used a mixture of anhydrous acetone and IPA to clean it up and ended up with 100mg of grayish crystals after redissolving in water and evapping.  So this should give some indication of just how impure mescaline can turn out, likely due to heat.  Also, unless everything that was pulled off was simply impurities from the cactus, apparently oxidized mescaline is soluble in either IPA or acetone.