As soon as the mimosa hit your stomach, your MAO would break dmt down.. Also when you smoke caapi vine/MAOIs, they are gonna go from your lungs to your blood and brain, they wont go to the stomach, so no matter when you smoke it, it wont inhibit the MAO in your stomach, hence it wont really work to activate oral dmt/mimosa.
And yes please as madcap said, use the thread title to help people knowing what is inside... I edited it, hope you dont mind.
Regarding changa tek, you first need to extract dmt and then dissolve in some solvent (which can be something as simple as vodka / ethanol) and then evap that onto herbs. Also I think you need to read up better on chemistry, solvents arent caustic, solvents may be flammable, or some of them may be toxic, but caustic = chemicals that can cause corrosion such as NaOH. But if you take the simple safety precautions (just as you do when you drive a car/use a knife/whatever), there is no reason to fear it. NaOH is used in the manufacturing of many food products.
In any case, you can always look into the food-safe teks, check the WIKI and the 'sustainable nexus' subforum, teks such as amor fati's will use only food-safe products to extract dmt. Good luck!