| Do NOT throw those expensive packs away yet! FMA Direct has a charger | called Cellpro 4S that has a special function for reviving packs that | were used too long
You don't need a special charger for this. As another poster suggested, just use a NiMH or NiCd charge function on the bad cells at a very low rate until they get up to 3 volts or so. Be sure to use a low rate and do not leave it unattended, just in case. If something goes wrong and the charge rate is low, it'll puff long before there's any pyrotechnics.
Also don't do this unless you can charge each cell individually (i.e. balance), because the cells are likely to be very out of balance.