The reason that solvents are used in the making of RSO is that it extracts ALL of the essential oils not just the parts that are psychoactive (get you high). In making RSO you also utilize the entire plant with the exception of the roots. It is the synergy between ALL of the naturally occurring chemicals that activate your own endocannabinoid system that helps to restore homeostasis which is the healthy balance a well functioning organism strives to achieve. Don't confuse specific concentrates and their effects with whole plant extracts, there is nothing wrong with any of the methods but it is NOT RSO. I will however side with the naysayers on the use of naptha as a solvent. My mentor swears by it but I have never used anything but grain alcohol as I feel it is safer. I believe that solvent removal no matter how complete will still leave some residue and I would rather be safe than sorry. In addition I make oil exclusively for cancer patients whose immune systems and bodies are already compromised and they deserve the best chance they can get which means the cleanest medicine.