Isopropyl alcohol extraction - freebase mescaline

I've ordered some 99% isopropanol, and plan to do an extraction sometime soon. I've been looking at a lot of threads on various forums, but haven't been able to find a solid answer to my question. Now, I know that the mescaline extracted in an ISO extraction is freebase mescaline, but how would you get a crystal or powder out of this? I've heard that the freebase oil reacts with the carbon dioxide in the air to form mescaline carbonate, which crystallises the oil. Is this true? I'm a total noob to the whole base/salt business, so go easy on me. I heard something about people adding vinegar to their ISO extract tars, but I'm still confused about the whole process.