I recently ran across an opened half-full bottle of Proraso aftershave balm with green tea and oats. It may be as much s 5 years old. It looks and smells OK. Does anyone know if it's fine to use or should I toss it? Thanks
If it looks OK and smells OK then it is OK. I have used opened balms that were decades old with no problem. The only balm that had spoiled was even older, smelled like sewage, and was quite obviously not usable.
Pretty sure that all you'd likely notice is off smells or consistency. I highly doubt that it'd suddenly become flammable, poisonous, or cancerous. Though I'm not a doctor, so YMMV. (Had to add that CYA in there...)