i'm not sure if there's an official version, but mostly it's the heat that creates the reaction
i basted it onto mine after having put the hair up and saran wrap on it to protect it..then i put them outside in the 95 degree heat...this was in july....
it took 3 passes for my yellow IT bodies
the process isn't specific to doll bodies, but to ABS plastic...so you can google things like retrobrite for general instructions