How do I research old stocks?

My grandfather just passed and we were going through his assets and came upon hundreds of penny stock certificates. Some of the companies we know are still traded and are worth something, some we know went BK. My question(s) are 1.) How do we know if he definitely still owns all of these and didn't just forget to send the certificate in, and 2.) how do we research any other stocks that he may have owned but doesn't have stock certificates for. He loved to diversify so we have already contacted all of his investment brokers, but we also know he did a lot of trading on his own direct with the companies, but just don't know who all of those are. I want to note that a lot of these certificates go back to the 1970's so way before internet record keeping & tracking would have been around. Is there a website that I can type in his name and social and find out his investment information (I know that's too easy). His will was very cut & dry about dividing assets, but didn't detail them.

Call a stock broker, or go to the library.
You can also check with the NYSE
He would of had to surrender any stock or certificates in order to make a trade so if you still have them and the companies are in business you could be rich.
So the best answer is a yet a broker and you will have to pay him a fee, but make sure that you record every item you give him so that you are not cheated, There are a few dishonest one out there.

check old news papers.