My favorite are
N (Nembutal), if you can get it as it is possible to get only in South America
Nitrogen gas method, if you do everything properly
Sn (sodium nitrite), if you follow the protocol
Ddma drugs mixture, if you can get the necessary drugs
Ddmp drugs mixture, if you can get all the drugs
I personally have my ways to get pure fent and heroine in the dosages i need, can't say the same for everyone though
How you gonna get pure fen and heroin?