He's tried it with THH, harmine, and harmaline separately, but not a simple caapi drink.
THH makes the trip more DMT-like and extends it. Harmine and harmaline make it more ayahuasca like, more potent, and also extend the effects. But if there’s any of the nauseating toxic crap present, they will increase the nausea of the toxic crap. So you need good quality seeds, or clean bufotenine.
I think the “toxic” crap in the seeds is actually bufotenine N-oxide. That’s my gut feeling. Some seeds contain a near 50:50 ratio of bufotenine and bufotenine N-oxide.
The xylene boil purification step (the details of this are found elsewhere on this forum) that SWIM performs on his bufotenine extracts would theoretically remove all bufotenine N-oxide because it’s more polar than bufotenine. The toxic stuff is also sticky and bufotenine N-oxide should be sticky just like DMT N-oxide is. So I’m pretty convinced the toxin being removed is bufotenine N-oxide.
Older seeds should have more bufotenine N-oxide present. Bufotenine eventually oxidizes into bufotenine N-oxide.
At some point when SWIM has more free time he plans to convert some pure bufotenine into bufotenine N-oxide using hydrogen peroxide (H2O2) and alcohol. It’s a simple procedure. You just mix bufotenine in a little alcohol to dissolve it and then add hydrogen peroxide while mixing and bufotenine N-oxide will form. My guess is that it will be an amber colored sticky material and will cause intense nausea when smoked, flushing, and all the other unpleasant effects some cebil seeds have.