Frank ;
getting to this later than most but will add my lesson s to this tread.
If you have the chance, take a meter and check the packs. If 75% of them are good , then take the whole thing.
Norm and NTL has become the gurus of making battery packs search <Bruce packs :-)>out of the good ones I've sent them.
Most of the older ones will be NiCds. ALL of the ones I've dug into have a tab on them that if you use it for connecting to take solder real well even from a small 30watt iron.
NiCds & NmHi packs can take much more abuse than SLAs of other Lead Acid based battereis can.
One thing about them is that if they have been sitting for two years then if you test the packs and read anything less than 1/2 of the rated voltage don't even bother as most of the internal packs will have begun the reverse their polarity.
IF however most of them do read a good voltage then rewiring them for the voltages you want is straight forward and easy to do.
In the case of the units that burnt, overheated etc. was due to a bad chip inside the "smart" set of for the LiOn ones. At this point I'm still learning how to deal with those, but since they don't like be out in the cold and heance are not any good to me I can't give you any thing to go on.
The ones that are NiMh will give you about 300 full cycles before they really start to lose their usefullness.
The NiCds, I have cells that are still good with date codes on them from 1999, that weren't even close to be cared for until I took ownership. And they still test at a rate of 90%+ of the original 1300mAh.
Since I use these packs for my Alky and hydroponics stuff I don't baby them. I do have one pack wired for 19.2Vdc and since it came with multiple taps, I sue the 12V side to run a fan for the peppers to polinate and the little 1.5 watt PVs keep them charged on the 19.2V side.
I wouldn't write these off too soon, but maybe they're a diamond in the ruff:-)
To disponse of the bad ones , should you take onwership of the piles, most of the battery places will take them off your hand for free, in small doses. One such place, that I've donated a couple hunderd packs to is Batteries Plus.
NiCds are also very well suited for e-bikes , since they give up their power much easier than lead based batts do and they're weight to power ratio is much much higher. I took out 3 12V18Ahr batts packs that weighed in at 80lbs and put in 3 sets of NiCd packs rated at 16Ahr and could go the same distance and they only weighed in at less than 1/3 the original. These are the older ones, not the new 2100mAh ones but older 1300mAh ones.
Hope this helps to muddy the decisions:-) just hate to see a possibility pass by.
Cheers
Bruce S