Samsung CLX-9250ND-XAA - Manual (Page 101)

Maintenance_ 101
7. Close the inner cover.
8. Take out the LSU window cleaning stick.
9. Locate the LSU window cleaning hole and insert the LSU window
cleaning stick.
Slowly push and pull the LSU window cleaning stick 4 or 5 times to
clean the LSU window.
10. Repeat the step 9 for all 4 LSU window holes.
11. Insert the waste toner container.
12. Insert the LSU window cleaning stick back into its place.