You may be able to add them to you MDE account with a phone call depending on the type of ticket you have so try that first. That way you can plan FP's ahead of time. They may need to connect you to the IT department.
I had a few old non-expiring tickets (one from around 1996 and two from 2002 IIRC) and was able to have them added to my MDE account by calling up. I had one ticket added to my account, another to my wife's account, and a third to my daughter's, who wasn't even born when the ticket was purchased, it was originally purchased and used by someone else. The tickets all have theme park admission on them and at least 2 of the 3 have a waterpark day on them.