FORD 2010 F-150 v.2 - Manual (Page 220)

For proper care of soiled safety belts, refer to Interior in the Cleaning
chapter.
WARNING: Failure to inspect and if necessary replace the
safety belt assembly or child restraint system under the above
conditions could result in severe personal injuries in the event of a
collision.
Seating and Safety Restraints
220
2010 F-150 (f12)
Owners Guide, 1st Printing
USA (fus)