[youtube]http://www.youtube.com/watch?v=pVtXT5WxTQo[/youtube] I bought a used DSI on ebay and discovered it had bad left/right shoulder buttons. I tried the blowing technique but that only worked for short spurts. Wanting to investigate I took it apart using the dissasembly guides on youtube. When I got inside to the actual buttons I discovered they were quite small and percision wired to ribbon cable making replacment almost impossible. I had read about soaking the buttons with rubbing alcohol and figured I'd give it a go. With the buttons hanging off the cables I carefully dipped them into a cap of 91% rubbing alcohol. I would let the alcohol work into the button and sit for like 7 minutes before clicking and blowing it out. I repeated this a couple times before reassembling. The first time I did this I tested the buttons like mad in DSI sound by making the cat/dog sounds and found it restored function about 90%. A vast improvement but I would still get random moments of no response. The next day I decided to takes it apart again and repeat the acohol treatment and after I found I had 100% function restoration and it's stayed that way for over a month now. So it was'nt that hard but of course you could break your DSI if your not careful. But I can confirm that this totally restored my shoulder buttons. I made a video for the DSI but I guess the ds lite, xl and 3ds use the same buttons so you should be able to perform the same procedure.