Why do electronics get destroyed when a magnet is near it?

Magnets do not destroy electronic equipment but they do influence their behaviour of shadow mask Colour Television Tubes in that the shadow mask can become manetised from a magnet close by. Magnetization causes incorrect beam landing on the pic tube which shows as multi coloured patches on the screen . The effect can be cancelled out by degausing the CRT using a degauss wand . All CTV have an auto degauss system to take care of impurities caused the earths magnetic field .