In case of aluminium i say it's a big concern
I used the same bottle for two extractions, cap is aluminium with plastic protection and on the second time the plastic protection fell while pulling and the aluminium started melting fast. I changed the cap and continued the extraction the solution was bubbling for some time and white solid pieces formed between the two layers i knew that aluminium oxide(not sure what form of aluminium was that) is soluble in nps but i thought this wouldn't be a big problem since the evaporation temperature is high. I made changa with it and tried it and i really regret it, i realised that aluminium particles can travel along the smoke even if they don't evaporate...
i'm still suffering till now. aluminium is toxic and it feels like my throat is perforated (i'd be dead by now if that is true) or burned. It doesn't hurt at all but it just doesn't feel right, it's been three weeks and i still get that ugly feeling in my throat for around an hour during the day and i feel completely healthy and normal when it goes away. i don't understand what is going on, i will see a doctor soon.
I'm afraid of smoking anything anymore so please be careful