How to reset to factory settings on Lexmark printers

Open the printer's web page and log in as administrator.
On the menu, select Settings.
Select Device.
Select Restore Factory Defaults.
Select Restore all settings.
Select Start.

This will restart the printer, restore all printer settings, fax settings, network settings, and app settings to their factory default configurations, and remove all non-standard apps.
Select Start.

The printer will restart.
Set date and time.