Thanks buddy, lesson duly learnt. Will keep that in mind for future.It could be, but at 0.1 volts or under, they are well dead.
These cells start to degrade internally if their charge drops below 2.5 volts. If left for months, they are too far gone to revive.
Whilst you can revive cells that have dropped below 2.5 volts, you shouldn't do so if they have been below that voltage for a long time.
Bin em.
If you intend to leave cells unused for a while, it is a good idea to store them with a half charge of around 3.6 - 3.7 volts and to check them every month or so.