Tyre shine is pretty damn good!
Been on 6 months now and admittedly it's been sat under dust in my garage most of that time but I did drive it home in the rain and I was sat outside for a while, but wipe the dust off and they're still a keep black with a nice shine to them still!
And tyre shine is made to stick to tyres which see all sorts of crap but they keep the shine for a few weeks, so put it on your plastics and it's staying long time
James