I have two smaller bottles of nic that have turned yellow. Is it still good and ok to use? I don't care if it changes the taste. I can always add more flavor. I just want to make sure it's safe to use. Sorry if this is a dumb question that's been asked before.
It's fine. When you buy nic, get it in the freezer ASAP. It's best stored in glass, so break it down into smaller glass bottles so that you aren't constantly opening the big bottle frequently.
Keep a small bottle out for mixing if you need to, but put that bottle in the fridge to slow the aging process. Nic at room temp will yellow fairly quick, but when frozen the process is slowed to the point where it can stay clear for years. My liters are frozen, but I keep a small bottle in the fridge for mixing and it's still clear after many months.