Seat belts often go ignored as a part of the motor vehicle's interior cleaning, mainly because many drivers simply don't know what to use to clean the tightly woven material. Over time, the seat belts become dirty and grungy from lack of care. The ribbing fibres break down and become loose, then start to fray. The weakened belts then have to be replaced at considerable cost.
Hot Soapy Water
The best product for cleaning seat belts is bleach-free soap and hot water. Soap and hot water work together to loosen grime, make-up and hand and body oils embedded in the fabric. Deeply soiled belts may require two or more hot water and soap baths before they are ready to sun dry. Always rinse thoroughly then dry completely before using the belts. Wet seat belts should never be rolled up in the retractor. Bleaches and dyes will severely damage the seat belt webbing strength.
Commercial Seat Belt Cleaners
Professional car detailers use liquid seat belt cleansers mixed with water. These cleaners are non-flammable and non-caustic so they don't destroy the seat belt fibres. Many also work well as spot removers for small stains, cleaning them away without requiring removal of the seat belt. Cleaning solvents and cleaners containing abrasives should never be used to clean seat belts.
Cornstarch and Talc
Cornstarch and baby talc can be used to remove grease stains. Brush off loose dirt, dried-on food and spills until as much of the loose residue as possible is gone. Cover the stain with baby powder or cornstarch. Leave it on the grease spot overnight or longer, then brush the talc or cornstarch off. Most, if not all, of the stain should disappear. However, if necessary repeat the process.