I recently got a letter in the mail from a company offering to help me collect my unclaimed funds. They kindly told me what state it was in and the company reporting it, which was plenty of information for me to go to the state comptroller's web site and find it for myself. It took me less than 10 minutes to collect $5k that seems to have somehow come from stock options that I never exercised and assumed they disappeared after the company got acquired.
The people offering to help me collect it are still sending me letters and text messages, long after the check has cleared my account.