Mtry gave the best and only realistic advice possible under the circumstances.
Modern TV's have a built in automatic degaussing circuit that will clean up any damage done by speakers (or other magnetic devices) being placed too close to the CRT. This circuit is activated when the set is first powered up and it's operation is invisible to the user. Of course, if the source of the problem is not removed, it won't do a bit of good.
So, keep trying. Slowly move the speakers closer and closer to the CRT until the colors distort and then back off an inch or so. Believer it or not, that's your answer.