Experts on R123 please help!

[pjandyho]

I have some unprotected DLG rechargeable batteries which I have not used for quite some time choosing to use primary CR123 for my SF lights. Here's what I have,

6 pcs 17500 1100mAh
6 pcs 16340 (R123) 600mAh

Thing is 5 pcs of the 17500 and 4 pcs of 16340 still holds about 3.6v to 3.9v power and I know that it is safe to recharge them and use it straight away. I am left with,

1 pc 17500 which holds only 15.4 mV (millivolt I guess) power
1 pc 16340 which holds only 68.3 mV power
1 pc 16340 which holds only 1.299 V power

Question is, is it safe to recharge them again? I understand that it is unsafe to recharge unprotected Li-Ion when the power is too low but how low is too low? Please help if you know.

Thanks.