dunno if this was mentioned, but odd colors could also mean you have a bad cable or connection to the monitor port (whether socketed or permanently affixed). try moving the cable around or the socket. if the picture/colors improves momentarily as you wiggle the cable, then that’s probably the problem.
as for the speakers, if you bought any computer speakers of fair quality, they should be magnetically shielded and can therefore be placed next to the mon.
No, the only thing to help is degaussing. If the monitor does not have that function or the stains stay it’s probably faulty.
But CONFIRM this first by swapping the cable and monitor. And move the speakers away, too.
Well if you can afford it, it’d totally go with a flat screen LCD, even a 15"… it saves so much space and it’s so damn light. I’m telling ya, once you go LCD you’ll never go back!