A friend just completed a small extraction on fresh homegrown T. bridgesii hybrid as per House's resin tek.
The result scraped as a dry powdery crystally tan/light orange resin. I didn't weight it but it looks like around 3-5g from less than 30cm of 6-7cm wide cactus.
I was wondering if there is an easy way to purify this extract further and get closer to xtals.

My first thought is to dissolve the extract in a minimal amount of hot water + citric acid then defat with naphtha and evaporate the aqueous solution again. Has anyone tried this? Any reason it wouldn't work?

Defatting might reduce the volume, but I wonder if there is much lipid/wax left in an already powdery resin as opposed to the tar resin that is often the result of water or alcohol extraction. Citric acid doesn’t evaporate and would remain, adding bulk to the final product. You might get crystals but not the kind you were aiming for.

Those are good points, thanks a lot.
Maybe defatting without acidifying the water since mesc supposedly isn't soluble in naphtha?
I know doing a small a/b and salting would be ideal but I do not have access to toluene or limo at the moment.
I'll try to post a pic of what the extract looks like.

Could you describe, step-by-step, in your own words, how you got to the product that you currently have? Just mentioning "House's resin tek" doesn't really ring any bells for me.

Have you seen the 'CIELO' ethyl acetate tek? A minor adaptation of that for your resin might sort things out for you.

Sure, I chopped the cactus, despined it with pliers, removed the skin and diced the ribs into pieces about the size of half my thumb. This was put into a wide cooking stainless steel pot.
Enough water was added so that the pieces are floating with a good amount of room above the bottom of the pot.
The juice of a lemon was squeezed, filtered through a coffee filter and added to the pot.

The mixture was then heated to below simmer (no bubbles, only vapor) for 2.5 hours with very very minimal stirring.
The cactus pieces were then strained and the liquid filtered twice, the pot was cleaned and the filtered liquid added back to it and heated again to the same temperature for reducing volume.

Once the liquid reduced enough that it started to get the consistency of a thin, slightly dilute maple syrup it was poured in a ceramic baking tray and put in the sun for evaporation. The next day it had solidified into a hard candy/glass like resin layer at the bottom of the tray. It breaks like shatter when smashing it or scraping it (scraping was difficult)

OK, no need to add acid to that as mescaline is present in the cactus in salt form (malate) anyhow - not to mention the lemon juice.

You could try mixing it to a paste with lime (calcium hydroxide) and water, then pulling with a suitable solvent. Salt the alkaloids out with citric acid or vinegar, depending on what solvent you end up using. Ethyl acetate followed by solid citric acid seems to be the optimal route to shiny white crystals, at least when starting from cactus powder. I see no reason why this shouldn't also work with resin.

Have you looked into the availability of solvents in your country of residence?

Thanks for the help, the ethyl acetate method seems very promising.
Unfortunately naphtha, acetone and IPA are pretty much the only solvents I can easily acquire in person.

I grow enough cactus that I can afford to experiment, I think I'll try defatting with naphtha and report back.
I'm also quite interested by the fact that so far it's been a completely food-safe extraction and the resulting amount of material is not outrageous to ingest (it probably fits in 4 or 5 OO caps). I might try defatting with peanut oil first to see if it pulls a worthwhile amount of impurities.

How about cleaning up the resin using washes of cold/dry acetone and/or cold/dry IPA?

What we know from past contributions here and here is acetone and IPA do not pull mescaline salt from the plant material.

Thanks a lot, I will try cold anhydrous acetone next.
I am currently trying to defat with naphtha, simply dissolving the extract in hot distilled water left a layer of insoluble goo at the bottom of the shotglass so I decanted and transfered to a tall glass, added about 3x the volume in naphtha, mixed thoroughly and let separate several times then retrieved the aqueous layer and discarded the naphtha.
I will let the water evaporate now and report back.

Here is the extract as it was straight out of the water extraction, 2.64g from around 25-30cm of cactus:
https://i.ibb.co/Q86Mm5V/P-20210614-200106.jpg

What is the weight of the goo versus the full resin? And the goo must be soluble in some amount of water, since you originally extracted using water?

Do you still have the naphtha? Curious to know what remains if you evaporate it.

Agreed, I was surprised to see how unsoluble the goo looked but I guess you're right it would probably dissolve in a (much) larger amount of water. I will dry the goo and let you know how much it weighs.
I don't think the naphtha pulled much of anything, no noticeable color change in the solvent or the aqueous layer. I already discarded the naphtha unfortunately, it was already used for dmt crystallisation a couple times before using it for this project.

Before the ethyl acetate tek came along, I was planning to experiment with purifying from hot water extraction. Good to see you're experimenting with this.

If you don't mind, please weigh the various intermediate products:

A) Straight resin from water extraction: 2.64 grams;
B) Dried resin after goo removed and naphtha wash;
C) Dried goo which did not redissolve in water;
D) Gunk removed by naphtha, assumed to be A minus B minus C;
E) Dried resin after washing with acetone;
F) Dried resin after washing with IPA;

For folks unable to get ethyl acetate, this might be a simple mescaline extraction tek that yields a semi-purified product. I haven't seen a process exactly like this one yet.

Naphtha, dry acetone or IPA will dissolve just very small fraction of the resin, imo it's not worth the effort.
For crystals, you would need to change pH from acidic to basic and back again, and use some solvent in between.
But you have rather small amount of resin, it would be probably better to just eat it.

Not all the cactus resin re-dissolves in water. Doubledog has mentioned this several before and is what I also observed. Not sure why, one possibility could be proteins that denature when dry, becoming insoluble.

You can also try add acetone to the re-dissolved water. Some proteins and maybe other stuff should crash while mescaline stays dissolved . I found that mescaline from a water extraction is very persistent staying in solution (doubledog had also mentioned this before), even after two volumes of acetone are added. Some kind of plant stuff must be helping it dissolve. If you use little water and a lot of acetone maybe mescaline will crash eventually (a lot of other stuff would crash first though). Solution becomes cloudy each time something new crashes.