[old_tv_nut]

Originally Posted by ppppenguin

You were lucky. If you put a pwoerful magent close to a colour CRT it will often magnetise the shadowmask to a point where the internal degauss coils can't cope. No problem if you have a handheld degauss coil. I have an old handheld bulk tape eraser which does the job nicely.

I think a REALLY powerful magnet might be capable of mechanically distorting the mask so that no degaussing will fix it. I would not try it for fun unless I was willing to trash the CRT.