If they are old, you are going to need to cycle the living crap out of them and hopefully break their memory. First thing you need to do is almost dead short those batteries. Hook them up to a light bulb from a turn signal (if a single cell, if a 6 cell, use 10 bulbs in series) and go down until it's just about to lose the glowing filament. Then, charge it. When I charged my batteries, they were 6 cells in series, and I charged at 5 amps. Your going to want to put a fan on them, or better yet, set the battery on top of the fan so it has direct air flow. These batteries get hot when charging at this amp rating.
Once it's charged, discharge it again as stated above. You can do the discharge with the charger, but you need to draw it WAY down and I don't think the charger will let you do it.
I raced rc cars for years running these batteries and this is how I charged them. My last charger that I got for them was a Reedy charger and was about $200.