I accidentally drained my 26650. Should I dispose of it or safe to recharge and reuse?
At 3.01 volts? Nah, that’s not even a “normal” complete drain. Most cells are good down to 2.8V in normal use, and some can even drain down to 2.5V safely. Just charge it back up and use it! 
Then again, if you’re worried about it, I can give you my address and I’ll dispose of it properly for you. 
@trailhunter, the lowest absolute safest voltage is 2,5V.
Did you have a hobby other than flashlights before?
Phew ok, was concerned I over drained my precious battery. Thanks for the feedback!
What is a “hobby”?
Drones, knives, etc.
Not 
quite. At least Sony (VTC6) and LG (HE2) specified “2V minimum” for some of its cells.
And I'll be honest. I harvested a few Samsung ICR18650-26C cells from a laptop pack months ago. A couple of its cells were a bit below 2V, and some of the others were pretty low too. I discarded 2 cells after some tests (the lowest capacity ones which also showed slightly worse self-discharge). The remaining cells were kept in a box. Some weeks ago gave 'em an equalizing charge to observe their self discharge ratio. For now there are small differences but overall they look pretty good.
I’m kidding 
… yes and I need more springs!
Cells begin to get damaged below 2.5V.
At 3V isn’t not even fully discharged.
That’s the resting / idle voltage, isn’t it?
I notice that after draining batteries in a flashlight, the voltage often recovers a bit (eg. I often test battery capacity on the MC3000 drained to 2.50v, but after awhile, the voltages begins to recover. High-drain good batteries can stay below 3.0v for quite some time after getting drained. But higher-resistance or poor quality batteries tend to jump very quickly up to higher voltages.
Say if I drain to 2.50v, but then let it stay that way for 1 day or several days, will the battery start getting damaged? (the battery voltage probably would have recovered to 3.0v or higher after a few days).
Everyone comes here and sings his/her particular son. The question is, what do you want to believe or how do you believe on a subconscious level? That's what matters.
In the above case, I wouldn't care. I've super slow drained batteries to around 2.5V (using an old 219B testing emitter as load) and the battery voltage recovered to nearly 3 Volts. It also recovers much faster than that.
Do I think there's many scaremongerness in all of this? Probably. ;-)
+1
It warms my heart to see how helpful people are in BLF, even to the point of properly disposing of dangerous items
I have tons of rifle primers lying around in my garage. Perhaps someone will dispose of them for me :partying_face:
Is this why DavidEF has an awkward amount of batteries?
I’m willing to dispose of any extra Benjamins one might have lying around. I’d even pay the postage. 
no, that is a normal discharge to 0% capacity. 2v would be something to be concerned about.
Yeah it depends on the battery ....but the newer cells are generally 2,5v is empty // and older cells were 2.8v .
the thing to do is give them at least a resting voltage of 3.7 volts and not leave it at too low of a voltage .At 3.1v. you have nothing to worry about .
Send those to Taofledermaus and let them “dispose” of those in a spectacular way! :partying_face:
Probably. 
I really do have rifle primers I want to dispose of. Free to anyone who wants to pick them up in San Francisco, CA (hazmat shipping would be a killer).
970 - Winchester WLR
140 - CCI 200
12 - Remington 9 1/2
Maybe I’ll post this in the giveaway sub-forum.