Honda 1990 Accord Sedan Owner's Manual page 18

Inspection
All parts of the seat belts, including the belt fabric, should be
regularly inspected for fraying, loosening, wear and other
damage. Keep the belts in good condition at all times to reduce
the chance of being injured in an accident, and to minimize any
injuries that do occur. Make sure the buckles, retractors,
tongue plates, guides and anchors all work properly.
Don't let anything get inside the buckle or the retractor; it
could cause latch or retractor failure.
Cleaning
The belts should always be kept clean and dry; wet or damp
belts can cause rewinding problems. To clean the belts, pull
them all the way out of their retractors and use warm water
and a mild soap; then let them air-dry fully extended, in the
shade, with the car windows open.
Never bleach, dye or clean the belts with chemical solvents;
it will weaken the fabric.
Do not remove the seat belts from the car to wash them.
Replacement
Replace the seat belt if:
1.The belting is cut, punctured, burned, etc.
2. The buckle or retractor does not work properly.
3. It was being worn at the time of a collision (also check for
damage at the seat belt anchor points).
4. Its condition is questionable.