Chemical Storage Timeframes: I was wondering if there are any guidelines that relate to how long chemicals can be stored in a secondary school prep lab before they go 'bad' - essentially a use by date? None of my chemicals have use by dates, but some are very old (from the 90's), and I'd like some information to forward to my HOD to back up my request for disposal. I've asked this question on a discussion list and someone replied with 5yrs, but didn't provide any evidence to support this.

Also is there a list of chemicals and their shelf life available to download?