Using Rubber Renue on Hardened Idler Tires?

[Captainclock]

Hello Everyone the other day I had ordered some Rubber Renue from Amazon.com to try and see if I could try and get the idler tire for my Zenith Microtouch 2G Record Player from 1967 going again (the idler tire had hardened into almost a plastic like consistency and was causing the turntable platter to slip mid cycle when I would activate the changer.)
And well it seems that possibly my idler tire might be too far gone to try and save using the Rubber Renue because I had quite literally slathered that stuff onto the idler tire and let it soak in and did it several times over a period of 5 hours this past Saturday, and it didn't seem to be making any difference.

Was I maybe doing something wrong, or is it that the idler tire is just too far gone to be salvaged?