I would just run them. The tires on my daily driver are about that old. I had them in storage for 7 or 8 years while I ran down the set that came with my car. I did 80mph with them on the way in to work today.
The considerably newer tires on the back of my wife's car started to separate tread from the casing. One wore through and just went flat on the highway one day, no catastrophic failure. The other one developed a super nasty wobble and I noticed the same tread separation when changing the tire.
Not exactly apples to apples but on our highway tractor/trailers we recently pulled a worn retread tire off a customer's trailer. The tread was worn but an inspection of the casing showed it was 17 years old and had been recapped 6 times and it was still in good shape. We have a trailer on our yard we use for putting around off-road only and the date on the casings is either 1990 or 1980 can't tell which.
Saturday I had a job at Bandag, they recap tires for a living, google them. In the process we discussed recaps and I was told pass car and light truck casings are too light duty anymore to recap. So they don't as they cannot be guaranteed.
I wouldn't run old pass car or light truck tires for anything more than getting it to the tire store for a new set and then only at city street speeds. If the are not so old as to be the old HD ones that could be recapped then they are a poor gamble and if they are so old as to fall into the HD category, they are too old for the rubber to have held up safely.
But if you want to gamble with your life go ahead play polish roulette but don't gamble with mine or anyone elses.
