one of my later pulls on a stb with xylene salted with sulphuric acid and re-x'd with acetone bomb, has minor contamination with sodium hydroxide i can tell by the powdery dull coating on the crystals, whereas the others are clear and sparkling. this was due to trying to get the last of the xylene out which was slightly cloudy, i filtered a few times but i guess it wasnt enough.. next time ill just leave the last bit.

now whats the best way to clean them? can i re-dissolve them in a small amount of xylene let it sit for a day then filter and repeat the salting re-x process? or is there a better way to clean them...

I don't think it's sodium hydroxide contamination, if you salted with sulphuric acid it's sodium sulphate. It's harmless but just as annoying if you want purity.

Yesterday I tried to purify my mescaline sulphate by dissolving in boiling anhydrous methanol. This should leave all anorganic salts behind. However, I discovered that it takes quite a lot of methanol since mescaline sulphate is only slightly soluble in it. For me this was not convenient at all (not enough methanol at home, no fume hood).

Next time I will try a second acetone bombing. Dissolve the whole lot in a minimal amount of water, add acetone and put in freezer. The mescaline should crash out, leaving anorganic salts behind. The downside is there is still some mescaline left in there that is not pure at all. Anyone know how much mescaline sulphate water at say -15 C can hold? Also, would all the inorganic salts in the water/acetone mixture prevent nice crystal formation?

yes sodium sulphate your probably right.. its just a waxy powdery coating the crystals still formed nice needles. i just thought that if i redissolve in water mix with acetone and re-x the same thing will happen and i wont get rid of the contamination, i wondered if i added it back to clean xylene and let it sit the contamination would settle out but i dont know if the sodium sulphate will act the same as hydroxide.. or if the mesc in salt form will even dissolve in the xylene. maybe i'd have to basify it first...

i could also try to redissolve in water and filter it several times through cotton filters hoping to catch the sodium sulphate.

hopefuly sombody with more knowledge will offer some advice!

Sodium sulfate is very soluble in water so it will dissolve if you add it to water.
I'm not sure if when doing the acetone bombing again the sodium sulfate will crash out just as the mescaline or if it will stay dissolved in the water/acetone mixture because it is so soluble in water.
But if you dissolve the whole lot in water, basify, pull with solvent making sure the solvent is clear, then salt with sulfuric acid in distilled water you will have a product without salt contamination for sure. I think this is what I'm going to do.

it seems that the contamination was only happening on the final pulls after over 1 percent percent had been retrieved, as the final pull i did was done perfectly clear solvent, well filtered etc just like the first few and it still doesnt look as sparkly and fluffy, i will still try cleaning them just to see what happens..

You said it is a ladder pull, it may be gunk inpurities that got pulled out of the solvent from over salting. You would probably be able to clean it up by re-A/B... dissolving in water, rebase, pull into np, and hcl salt out followed with evaporating.

thanks kash i will try re-ab i highly doubt its over salting though as all the later pulls were titrated too between 6-7 with a digital ph pen, and earlier pulls that i over shot slightly around ph 5-5.5 came out perfect after the dual solvent re-x with acetone