Most vape shop waste comes from one mistake: buying too much of a new brand on distributor recommendation, then it doesn't sell. The rule of thumb: never buy more than 3 boxes of a new brand initially. Test it for 30 days. If it sells, reorder. If it doesn't, you've only lost £30-50.
For stock that's already at the 60-day mark, run a promotion: 'Buy one, get one half price' on that flavour. Move it before it becomes a total write-off.
TrackElf flags slow-moving stock at 60 days, so you have time to act before it expires.