Additionally...
There's less in the sticky thread than I thought about degaussing... and BR only mentions some of this in passing.
(If your monitor's degaussing coil is good, and plugged in, and the and circuitry is working...) Your monitor degausses itself every time you turn it on cold. This is usually accomplished by a thermistor that warms up, increases resistance, and stops flow to the coil. As a result, the degaussing is very brief, and will not recur immediately if you just power cycle the monitor/game. You must wait for the thermistor to cool down before it will permit current to flow to the coil again; give it an hour or so (though I haven't actually measured the time required).
The point is that a "wait and see" approach may work. I recently put a game in my garage, and at first it had some definite discoloration--it needed degaussing. I was too lazy to go get my degaussing coil, remove the glass, etc, so I just left it. After a week or two (and a dozen or more cold power-ups), it had "fixed itself." The degaussing coil operated briefly every time I turned it on, and finally the discoloration was completely gone.
If your degaussing system works, you are patient, and the magnitization isn't "too bad", this may work for you. If your degaussing system is jacked, or if it's "bad enough," manual degaussing with an external coil may be required.