Your seat belts can save your life and many people are still alive because they wore them. Here at 1stCertified Collision Center, we often work around seat belts, so we know that they are necessary to car safety, and that’s why we often stress that folks wear them. Your seat belts will get on-going daily wear from liquid and food spills, filthy hands, and oils from peoples’ (and pets’) skin. With national safety campaigns, we know the importance of wearing our seat belts, but do we ever think about cleaning them?
The sad fact is that most car washes and even professional detailers don’t normally wash seat belts. So, if your seat belts have not been cleaned since you got the vehicle, it may be time to refresh those babies.
To get started, open your vehicle’s door and carefully pull the seat belt out of the retractor. Utilize a simple clamp to stop the belt from retracting back into the spool while you’re cleaning it.
Next, evenly spray some fabric cleaner on the fibers and scour them with a gentle brush. Rub in the direction of the fibers and don’t use a circular motion (basically, avoid circles). 
Over time and with excess pressure, the webbing on your seat belts will start to fray after heavy usage. If any of the stains on your belts still won’t disappear, water down some all-purpose cleaner in a little cup of lukewarm water and then submerge the brush into the cup. Then, apply some elbow grease to that area of the belt. Don’t use too much cleaner or a brush that might damage the fibers.
For seat belts that are particularly stinky, vinegar is great at eliminating offensive odors, because it is a natural antibacterial agent that can knock down even the worst aromas.
To minimize future mold issues, you might need access to a steam machine. In this case, spray fabric cleaner on the belt and use the machine on the webbing to blow the dirt away and kill those pesky germs in the process. Steam is your best friend in this regard, but it will allow you to mitigate the moisture and then dry it out quickly.
After the cleaning process is complete, let your seat belts have enough time to air them out completely. This way, they can dry out and any chemical smell will promptly go away. If you can follow these simple steps, your valued seat belts will be clean and pristine and ready to protect you one more as you drive!

Sources: About.com, AAA and AARP