Yes YOU can REDUCE screen burn, a joint one of my friends interned at in the 80's (when monitors were worth fixing) he worked at a place that refurbed monitors. To reduce screen burn you need a device to scan the monitor accurately and reproduce the video signal that caused the burn in reverse, however for this to be effective without wasting months one needs to be able to turn up the cathode voltage a significant amount and run the monitor until the background of the screen is burned nearly equal to the "burned" area. This has the side effect of dimming the screen slightly but a modest jump in voltage fixes that.
Remember even if done correctly the burned area will still look a little uneven but not as much as if you did nothing (this works best on mono monitors)
Cheers
Ryan