Symptom: Ghosting lines overlaying typed text:

This is assuredly not a type slug cleaning issue and the secret is that the loops in the letters like "a", "e", "o", etc. are clear. The lines are caused by the paper not being held to the platen, so when the slug hits, you're getting ink from the other part of the slug transferring to the paper. The remedy is to tuck the paper underneath the paper bale and rollers.

If one still sees issues after this then check your manual to ensure that the ribbon is properly threaded followed by a check that the ribbon vibrator isn't bent too far away from the typing point and too close to the platen and causing the ribbon to rub against the paper.