[Newellin Thunder]

Sorry to say that the chances are your batteries are ruined. It is possible to refill and cover exposed plates and then recharge. However, much depends on how much and for how long the plates were exposed. The problem being that the portion of the plates exposed can be damaged, resulting in a battery of the same Voltage but reduced capacity (in effect there is less plate area available for use). Once the damage is done there is no way to reverse it. Worst case the plates can short out, effectively remove them completely from the battery's capacity. If they aren't performing like they should, they're probably beyond hope.

Check the specific gravity in each cell. Look for low and inconsistent readings. If you find that you can try an equalization charge to try and bring low cells back to normal. That's about all you can do.