I get these cards from Capital Recovery Services every now and then. I googled them and immediately found results of negative nature. What I learned through the process is that ANYONE can do their own search for unclaimed property or funds easily by going to the State Comptroller website for any state you have lived in and inputting any name you have conducted yourself under. More involved for women because you have to search your maiden name and however many married names you have gone by. (Did I really have to get married three times?) But within three months I received refunds from an old cell phone carrier, overpayment of insurance premiums, and a couple of refunds due that weren't worth recovering since they involved acquiring former spouses signatures and who the heck knows where they are off to these days.
You can do it yourself and know that when or if you have to provide sensitive identifiable information about yourself you are on a secure website.