Oki MC860n MFP - Manual (Page 133)

Maintenance > 133
3. Moisten a soft, clean, lint-free cloth and gently wipe the LED head surface.
4. Close the top cover and press down firmly so that the cover latches closed.
5. Gently lower the scanner.
CAUTION!
Do not use methyl alcohol or other solvents on the LED head as
damage to the lens surface will occur.