A couple of strategies from some very old notes:
 

This segment will fill in each fog zone as visible, and does not require CLEO commands.

:sub_CG_Debug_UngrayMap
//RBR/CG37: Seemann's Map Ungray Codes
for 0@ = 354164 to 354188
  0001: wait 0 ms
  0004: &0(0@,1i) = 16843009 
end

This segment will write a large number to the fog count so that the gray zones are ignored. So... with a good mapping tool you could still track where CJ has been before, but it's awkward to see and hardly worth the trouble.

//OSR/CG37: Add 0x010000 to the grayzone count so all areas are displayed.
// *can later subtract 0x010000 to undo the change
0A8D: 0@ = read_memory 0x0ba372c size 4 virtual_protect 0
000A: 0@ += 0x010000
0A8C: write_memory 0x0ba372c size 4 value 0@ virtual_protect 0 // less destructive Ungray the map
//0A8C: write_memory 0x0ba372c size 4 value 0x010000 virtual_protect 0 // Ungray the map 

Edited Tuesday at 06:41 AM by OrionSR