I've not tried it with a translight, but this sort of UV-induced yellowing can easily be reversed by the use of a strong Hydrogen Peroxide bath and (perversely) exposure to strong UV (sunlight will work). I've used that technique for a number of plastic parts, and it is almost miraculous in effect. The only issue with a translight would be potential reactions with the image dyes, so I won't say "do it", but maybe someone else has tried?