Speaking of clean-rooms, I'd been vaping for about a week when I met the owner and mixologist of a juice line. He makes the juice at home, but he made sure to tell me that he has a clean room. I assumed that he meant that that room in his house was clean, but not the others. Only later in the conversation did I realise that wasn't what he meant and he then explained what a clean-room is.
Hyphens are important:
Clean-room means a proper mixing room, meeting health standards re air purity, stainless steel counters etc. etc.
Clean room simply means a room that is clean!
Or a laboratory style where it's easier to keep things clean. I have been in a lab and believe it or not, I want a lab style room for my stuff - not only ejuice but I work with herbs too for food and medicine. I harvest, clean, dry and then package the dried / grinder herbs into tubs for the winter.