So only a master could do it. The purer the reagents, solvents, and starting materials the purer the product.
I'm thinking that most drugs are going to loaded with impurites for that reason. Battery acid, lead and all other kinds of poisons were found during prohibition in illegal hootch smuggled from canada. PCP is usually loaded with impurites. Not only that you got old Russian weapons being sold on the black market to Terrorists. We got all kinds of biochemical agents being developed for weapons. Thats the last thing we need is some rapper babbling about his dick.