I think the best solution to preventing dust from getting under the screen is to actually seal up the gap between the layers of the screen (see pic below). I, and a couple other crackheads, have done this and it's worked great. Even though my phone is a newer build that didn't have dust problems, applying the seal gives me a lot more confidence.
Of course, no one should have to do this to prevent dust from getting into their phones, but that said...here's how to do it if you're so inclined...
CAUTION - If you aren't comfortable taking apart your phone and handling small electronics, DO NOT ATTEMPT this! Also, keep in mind this technically voids your warranty though 1) you can avoid detection by carefully removing the warranty sticker and 2) you can always remove the seal if needed - this is completely reversible.
1) Get the right tools and materials. You need a T6 screwdriver, a phone prying tool, an x-acto knife and thin electrical tape (compare the thickness of various tapes on the packaging). An alternative to the phone prying tool is any other hard, thin plastic (NO METAL) edge - those plastic keyrings from Borders, grocery stores, etc. seem to work.
2) Take out your battery, micro SD card and SIM card. Very carefully remove the warranty sticker covering one of the back screws and stick it on a non-stick surface - like the backing stamps come on. You can gently pry off the sticker using a small safety pin or needle. I recommend leaving the sticker on a non-stick surface and placing it aside for safe keeping.
3) Take the phone apart following this video - YouTube - BlackBerry Storm 9500 disassembly tutorial
4) Take the screen out and clean the sides between the two layers of the screen. If you already have dust in the screen, try using a vacuum to get it out. DO NOT try to blow it out with compressed air - this will only force it further in. If you can't get it out you can consider getting a new replacement from Verizon.
5) Cut a strip of electrical tape to cover one side of the screen. I found the easiest way to cut the strips is to use the x-acto knife to cut it directly from the roll of tape. Just place the blade at the beginning of the tape near the edge (the strip should be as wide as the thickness of the screen) and slowly turn the roll. I recommend cutting each strip a little longer than the length of the side you're covering. Make sure each piece you're cutting has one side from the edge of the tape - this will ensure one side of the tape is perfectly straight.
6) Apply the tape to the side of the screen, sealing up the gap between the top 3 layers (see pic below) . Line up the straight edge of the tape with the top of the screen. Once it's all lined up, take some time applying pressure on the tape to ensure it's all sealed tight. Carefully cut off any excess tape from each end.
7) Repeat step 5 and 6 for each side.
8) Once complete, your screen is probably a little dirty. Now's a good time to clean it off.
9) Before putting your phone back together, give each side of tape another press for good measure.
10) Put your phone back together. Make sure the 2 top and 2 bottom screws are nice and tight. Also, I wouldn't put the camera cover and bottom cover on until you've powered the phone back up and tested the screen - just want to make sure everything is working properly.
I know a video or pics would have been better. But, my phone's back together and working great, and I'm not willing to take it apart again - sorry.
(photo credit to TBacker)
http://forums.crackberry.com/attachm...creen-edge.jpg