We are made of chemicals...no getting around it. Homeostasis is like the journey that never ends. There will almost
always be some chemical imbalance, no matter what we do.
By your definition of clean, I think nobody is. Not even the weird vegan tribe (no offense raw food people) or hardcore AA/NA people with their chocolate and cigarettes (mmmm!)
A better definition of clean? For me, and for what I meant on this board - I think it has to do with one's primary drug of choice mostly...you know, that
thing which was considerately killing you?
The hard physically addictive stuff. The mean and the nasty, the killers.
None of us gets out of life alive, it is to
live while we are in the best shape we can, right?
So I do not put 'too much' analysis into how many Cokes I drink in a day (although a dear friend of mine likes to remind me occasionally, but I think it's because she's been misled by Pepsi)
Clean - like sober - is a relative term...I don't push it on myself for once in a while letting my hair down and having some fun (yes this can include chemical euphoria) or think I am not 'clean' because of tobacco.
Hell the emissions from automobiles in the city you can't even detox from those!
So for me 'clean' means living in a different way, walking on the journey to more spiritual cleanliness - spitting out that four pronged hook that almost killed me and wrecked (or more accurately - made ME wreck) so many relationships...my drug of choice which was heroin.
If I smoke weed regularly and never stick a needle in my arm again, I'm clean dude...

Good topic, thanks!