The solution is a reverse vulcanisation process that effectively creates new rubber from old tyres.
From the newscientist.com
Tyres also contain sulphur, which is added as part of the process of vulcanisation that makes rubber into a suitably resilient material.
From the economist.com
The condom was invented in the 16th century and the only significant improvement since then has been the vulcanisation of rubber in the 19th century.
From the newscientist.com
It was only when the American inventor Charles Goodyear discovered vulcanisation that rubber became the practical industrial product that we know so well today.