I found some old bank account books, their accounts inactive for decades. I'm reasonably certain the accounts were never closed, and even with no interest their value justifies recovery effort. I have contacted the bank but they have been less than helpful, refusing to tell me anything beyond "we keep records no more than 7 years". I have checked a couple of those unclaimed property sites online without success, but there are many such sites and perhaps I'm not using the best one. What are some ways to track down old bank accounts?