Then just recently I came across a blog that said there was a off the shelf product that was ready to use as is.
So as I have got some GameCubes with yellow-ish controller ports which do not clean with conventional cleaning products I decided to try the RetroBrite way.
I dont know if the staining is nicotine or sun ageing but it sure looks ugly compared against a clean controller port.

I put a strip of tape on the port to see if there would be noticeable difference.
The process itself involved applying cream peroxide with a toothbrush all over the discoloured area of the port and then covering it in cling film which helps to stop the cream drying away.
I then left the controller port outside in bright sunshine for a total of four hours of which it was cloudy for about ninety minutes.
After which I washed the port to remove the residue peroxide.

Remarkable difference - image on screen fails to deliver the true change seen.

The products used - Jerome Russell 12% Cream Peroxide - Kitchen cling film.
I got the peroxide from Superdrug (£1.52) retail chain store here in UK.
Here is the blog that brought this product to my attention - Thanks guy. http://stiggyblog.wordpress.com/2011/04 ... ter-cases/