Guaiacol isn't subtle.
Story time:
I bought a bunch of oils like test base, tren base, dbol, anadrol, superdrol, etc. I knew guaiacol is commonly used for some of them. I hadn't encountered guaiacol and I was wondering if I'd be able to recognize it and figure out which had it and which didn't. I have a poor sense of smell so I worried it might sneak past me
The first time I pierced the tren base vial, I knew exactly what guaiacol smelled like and knew I couldn't ever mistake it in the future. Trust me, you will know it when you smell it. If you aren't sure, then it's not guaiacol.
I have a soft case where I keep my open vials for my current cycle and PWOs. That case now lives inside two Ziploc bags to keep the odor from permeating the room.