Hi @unclefloat
Here's the [document|41215] section from the service manual for the monitor that will help.
Follow the procedure to remove the LCD panel.
Hopefully this will allow you to ''very gently'' clean off the oil residue from the screen's surface. Perhaps when it is clean, wipe it over again with a lint free cloth, slightly dampened (not dripping) with Isopropyl Alocohol 99%+ (available from electronics parts stores) to ensure that the screen is really clean before reassembling the monitor.