SWIM took an old ayahuasca brew, filtered it and freebased it with sodium carbonate.

The stuff that dropped out was collected, and messed with, etc.

The liquid was way overbasified with lots and lots of sodium carbonate and left to sit for weeks. The resulting sediment was washed with 99% IPA (hoping to collect the crystals from the coffee filter without collecting the excess sodium carbonate).

The alcohol didn't pick up much, but what it did collect was a waxy, yellow substance that resembled freebase DMT precisely. When still in the alcohol, it glowed a bright bluish green under a blacklight, says SWIM.

What is this stuff?

freebase harmalas are not very soluble in IPA, thats why not much dissolved... there was probably a lot of actives still in the sediment, so if you didnt throw it away, you could wash it with water to remove sodium carbonate, and (at least most of) the harmalas should remain undissolved in this water

I guess what you have there is a mix of harmine/thh..

Just room temperature, ph neutral water will leave the harmalas behind? About how much water would you say?

well it wouldnt be ph neutral because as you said yourself, there is excess sodium carbonate in that precipitated stuff so the sodium carbonate would dissolve in the water and raise the pH.. Or you can prepare a solution with a bit of sodium carbonate (not saturated!) just to make sure it will be with a sufficiently basic pH even if there isnt much sodium carbonate in the precipitates, so that the harmalas are not absorbed...

I dont know how much water because I dont know how much stuff you have there.. But just to say some number, you could predissolve a bit of sodium carbonate in 100ml water, and then add this to a container with the precipitates, shake the hell out of it, and then collect precipitates again, which should be free (or freeER) of the sodium carbonate contamination

Well, this dissolved most of the alkaloids. The reddish brown colored alk that would not dissolve in the alcohol immediately went into the basic water.

SWIM added more base in the hopes of dropping out the dissolved alks, but not much came out.

SWIM is thinking about just evapping the whole thing and using a bunch of anhydrous IPA to slowly extract everything out of it.

wash away the baking soda with water