Dyeing seat belt, even washing, can change the belt fabric is bad ways. Dye can reduce belt strength.
Rit and many other won't work. Dye that works will "attack" the Nylon and alter the chemistry. May look ok to you but tension strength can be reduce allot. Not Good in a wreck.
Pull out the belt and carefully block the belt from retracting.
Clean with Simple Green, Woolite, etc. then let belt dry completely.
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)