WD–40 does not technically expire, but it may deteriorate over time. WD-40 is a petroleum-based product, so its chemical composition is prone to breaking down over time.
This means that it may become less effective or even less safe to use after a certain period of time.
The best way to determine if your WD-40 has gone bad is to check its smell and consistency. If it smells off or has separated into different layers, it may no longer be safe to use. In this case, it’s best to dispose of it and buy a new can.
If it meets those two requirements, it’s probably okay to use – although, if it’s been over five years, it may not be as effective as you’d think it is.
Does wd40 freeze? Find out here.