This sounds odd - but..
..vegetable oil is the answer!
(Didn't try the extra virgin one, my rubbers aren't that posh!)
Was giving the car a bit of a wash today. Thought My Wheels looked a bit tired. The I remembered how much the Wet n black stuff CJ had at the Limerick Mett reminded me of ordinarey cooking oil. So I figured I'd give it a whirl.
Lo&Behold - Ordinary el'cheapo (think it's from tesco or summat) veggie oil does the shiny shiny job. Handy. But Why stop there?
My wind deflectors are now black again.
My Rubber seals are now black again.
The Plastic strips on my doors are now black again.
The Plastic strips around the windscreen is now black again.
In short - this stuff works on most parts - I did however find that too much of the stuff does look at bit crap.
I'd recommed putting a bit on a yellow sponge - run over the area you want to spruce up - then remove any excess with some kitchen roll or an old cloth afterwards.
If you get too much oil on a surface and leave it - it'll start looking a bit off after a couple of hours.
Nothing ventured - nothing gained
Next from Muads box of budget bits..
How to convert your comodore 64 to a Pentium 60!