I have side panels out and a clear view of the entire seat belt mechanism but it's still in the car. Are there any tips and tricks other than just soap and water? I'm hoping that a good cleaning will help the retracting mechanism work a little better.
Soap and water is a good place to start - it's always best to use the mildest cleaner required, especially on seat belt fabric.
I have done them before with the upholstery wand on my carpet cleaner. Worked well.
I always wanted to try a pressure washer, but I think you would have to have it out of the vehicle for that. Pressure washers sure do a wonderful job on floormats.
I have used Simple Green on belts, too. But like Stuart said, start mild.
My NC seatbelts retracted better after I cleaned with dawn and warm water and scrubbed. Then let it dry.