Back when Super Smash Bros. Brawl came out, there were quite a few Wii owners that found they were unable to play it. The issue seemed to be with reading the discs, as the title was the first to use dual-layer DVDs. Nintendo claimed that the problem was that the lens was simply dirty (caused by dust and smoke), and you would unfortunately need to send your console in to be cleaned. It wasn’t a great solution, but it worked. Well now Nintendo is leaving the cleaning up to you.
For around $8 you can pick up an official Wii Lens Cleaner Set from Nintendo. Thankfully I haven’t had any dirty lens issues thus far, but if I do, I’d be much happier trying out one of these, rather than sending my Wii off to Nintendo.