As we are not scientists we do not really know. Volatile chemicals have been used for decades to get all kinds of concentrates we use every day. If done properly these volatile substances are removed.
For people making concentrates at home unprofessionally, yes, this is considered to be clean.
If you want to save a lot of money, time and be better to the earth, while truly experience cannabis, consider a vape like the Silver Surfer. We call vaping doing raw dabs, as you are vaping the concentrates right off the plant.