SOLUTION #1 - debris on the glass
Any dots or smudges on copies come from debris on the main area of the glass, any continuous lines originate from the strip at the left side.
Wipe off any debris. If it is a dot or smudge of Wite-out, scrape it off with your fingernail.
SOLUTION #2 - Cleaning the primary corona wire
Grip the waste toner container with both hands at the top surface and unsnap and "fold" it down carefully to lie on the open front cover.
Move the waste toner container as little as possible.
Pull and push the handle in and out of the machine 20-30 times (fairly quick is fine)
Carefully replace the waste toner container until it snaps and holds into place.
Close up the front cover and you are finished! If any lines remain, call it in for service.