Does anyone know anything about doing this?
The screen has turned bright pink and I found out if you use a demagnetiser in front of the screen , this removes the colour.
Is it this easy?
The demagnetizer is called a degausser. The TV does it automatically every time it is switched on, it's very rare to need to use an external degausser.
If the whole screen is an even pinky/purply colour, it's likely the electronics driving the tube have failed (specifically, you've lost the green drive and are seeing a mix of red and blue = magenta = pink).
It's also possible, but pretty unlikely, that the tube has failed.