Let me repeat that older tires are not suitable for use at the upper limits of their pressure rating in my experience, but are relatively safe at lower pressures if such pressure is suitable for the rider's weight and conditions. I have too many bikes to buy new tires for. I thus have had to select from discarded tires, which I have a lot of experience doing by now. Luckily I am light enough to run the lower pressures that have proven suitable for use with older tires, up to 15 years old in some cases. The really old tires suffer tread wear at an alarming rate and are generally too fragile to trust fully. And any used tire could have suffered trauma or chemical exposure, etc., so be careful.