sometimes you can get by with holding the butt of a soldering gun up to it (a gun, not iron) or possibly a drill.
I use a bulk tape eraser and it works great. I bought a realistic bulk tape eraser for $10 on craigslist.
its easy to use. while the eraser is close to the screen, push the button, make big circles and move farther from the csreen and release the button.
the whole procedure should be around 5 seconds