Samsung SF-5800 - Manual (Page 85)

3.12
Maintenance
5. Carefully wipe the scanning glass with a soft, dry cloth.
If the glass is very dirty, first wipe it with a slightly dampened cloth,
then with a dry cloth. Be very careful not to scratch the glass surface.
6. Replace the roller in reverse order, and then close the control panel
firmly until it clicks into place.
4. Clean the ADF rubber piece also.