The black Laquer finish on your LSi's is a really nice quality finish, but needs to be treated with care. Over time the use of household cleaing products like Pledge (anything with oil in it) will deteriorate and ruin the finish.
For simple everyday dusting, use a slightly damp soft micro fiber cloth and then dry with the dry side using a front to back motion. I have also used a swiffer duster with good success.
For that couple times a year to polish them, clean as above, and then apply a light spray of Gibson Guitar Polish (AIGG-910) and buff to a perfect luster... Always make sure you are using a perfectly clean cloth because any foreign material will scratch your black laquer and usually can't easily be remedied.
I have used this stuff on guitars for years on my LSi's since I got them with total success.