Trouble with shoulder buttons

I have owned two Nintendo DS since the release one being the original, and the other(the one I own now) a DS lite. Both systems have seemed to give me the same problem over time, whereas the shoulder buttons (ie L and R buttons) would stop working. I can't say that I feel ive been overly aggressive in my use of the buttons to merit them to just stop working. I read at an earlier date that this may be caused by dust getting underneath the respective buttons and blowing inside them could possibly fix it. While it seems to work on a marginal basis with the R button the L seems to be much harder to get working. Short of sending it in or buying a triwing screwdriver, I was wondering if anyone had any other possible solutions. Any help you can offer would be greatly appreciated.

Thank You.