Nintendo - News - Super Smash Bros. Brawl Game Disc information
Nintendo are offering a lens cleaning service. You must contact them through the link on the page linked to, and then you have to send your Wii for them to clean the lens. They, obviously, warn you against cleaning the lens yourself. It means an inconvenience because you can't get brawling but at least they are aware of the problem and trying to sort it.
Bring out the SSOA if this has been done before, but I can't remember seeing it.