I have some FO I got over 6 years ago that I obviously need to get rid of (since I haven't used them up in this length of time they obviously aren't good sellers) but they are still in good order. My scents are kept in my warehouse which is a metal building. Our heat index has been around 115° last week. But it's true what was previously said, if you pour it into 175° and up this heat wave is nothing. The only problem I do have is when suppliers use those cheap bottles and they do the "sucky" thing and sometimes the plastic splits.