I see. Thank you that's helpful. I actually thought I had thrown away my SN but I found it. Unfortunately, the bottle does not appear to be airtight (It's the loudwolf brand back when you could get 100g or so on amazon, I had opened the airtight seal to put some in a smaller container) i do not trust it ,and it would be responsible to start fresh. If anyone has advice however and knows if my bottle is likely still fine I'd appreciate that too. I purchased it 5 years ago (also when it was opened once, then capped, but again i squeeze the bottle and i see air can pass ). I looked up ways of testing but they seem complicated, and one site had test strips that wouldnt tell me purity and would only turn blue if SN present.( also they were like 70 bucks, blech)