http://www.rctech.net/forum/11970495-post6.html
I have two 3S packs that required venting of cells 1 and 3 over a year ago, and they are still going strong, albeit with some degredation as they are 3 years old and hundreds of cycles old now, but 5000mah packs are holding ~4900 and running strong. These were FastRCBatteries.com packs.
A third 3S pack of the same make as above had cell 3 completely fail on me after a venting. That pack was cut down to 2S and still holds 5100mah to this day.
However, I also had 4 Gens Ace 2S 5000mah 40c packs at one point, every one of them requiring venting of cells 1 and 2.
2 of them are still going strong 10 months later.
2 of them required a second venting 2 months later, ending in both batteries slowly leaking gases that reacted with the hard cases and softened them a lot, making quite the icky mess. Both batteries had a failed cell 1.
I took the two good cell 2's and stuck them together for another 2S pack. I'm still running it with the other surviving 2 packs, no issues.
As always - My stories are probably unusual. I'm an Electrical Engineer with a mean cheap streak when it comes to things like this, and I'm sure I'll have a Li fire on my hands one day. This is
NOT safe. Please take caution if you are screwing around like this with LiPo packs. These packs, however reliable they have proven themselves this far, are still to be watched CLOSELY and will be suspect till the day I throw them out.