In certain cases, clearing electromagnetic buildup from a CRT monitor may be required to improve picture quality. This is called degaussing. It is rarely necessary to do this operation, but sometimes it may help. Here is how to do it.
1 Method 1
2 Method 2: using a tape eraser
3 Method 3: using a soldering gun
Most modern computer monitors have a built-in degauss function. Turning the computer on and off will often be enough, as they degauss automatically when turned on. You will know if the computer is degaussing itself because it makes a typical "dwoing"-like sound and, in some cases, distort the image on nearby screens.
If you do not hear this sound, press the computer's Menu button. Find a Degauss option and activate it. You will hear the sound, and the picture will be distorted for a few moments.
Method 2: using a tape eraser
If the monitor does not have a degauss function, you can use a bulk tape eraser:
Hold the tape eraser about 12" (30 centimeters) away from the monitor, and witch it on.
Approach the monitor easily, and swing the eraser in a circle over the screen. A field distortion will be noticeable when you approach enough. Continue moving the eraser, slowly taking it away, until you no longer see the lines
Method 3: using a soldering gun
Take a soldering iron and point its tip away from the monitor.
Place it in the middle of the screen, keeping it near the monitor. Turn it on.
Move the soldering iron along the edges of the screen, then put it back into the center of t