British researchers may have found a way to make the previously vulcanized rubber adhere to new rubber so that it can be reused. By grinding up old tires and then treating them in an ionized oxygen plasma chamber they have been able to get the carbon bonds to break and adhere to new rubber particles. Once that happens the rubber can be reprocessed in to new tires. Similar process have been tried before with chlorine or flourine but using oxygen is definitely less risky.
[Source: New Scientist Tech, thanks to Howard for the tip]