How to restore seat belts?

[blown motor]

Like the title says. Paint? Dye?

[Blowout]

You might be interested in a higher level restore but on my daily driver that has black belts, I simply soaked them over night in a bucket with the purple Super Clean/water mixer and washed them the next day with some slight water pressure.  I clamped them so they were fully extended in the bucket.  I couldn't believe how much junk came off of them just from sitting in the mixture. The belts looked brand new after that for me at least.

[BIGSHCLUNK]

Years ago sent mine out to Sharon's Web (as I recall). New plating/labels/they still look great. Never did on my own Murray

[anlauto]

I've used fabric paint before, you used to be able to buy it a CDN Tire

[72 Challenger]

A few squirts of spray and wash, let it soak for a day and then I put mine in a couple of pillow cases and ran them through the washing machine.

[moparroy]

I just cleaned mine as well - light scrub brush - don't recall what I used for soap - probably either dish soap or spray-9.
If they are sun faded then different story.

[anlauto]

A few squirts of spray and wash, let it soak for a day and then I put mine in a couple of pillow cases and ran them through the washing machine.

Does your wife know you did that ? 

[blown motor]

@moparroy  What are those belts out of? Are they correct for that model of vehicle?

[moparroy]

I believe that the driver's seat belt is original to the car - '74 Cuda 360 Canadian car. The labels on the fabric match what is in the parts book and these belts were in the car when I got it.
The passenger belt is not original and is not e-body - but it is very close. I modified it for now to use until such time as I might find an original one. On the passenger side this car had some kind of accident where the second leaf in the leaf spring caught on something - broke the tip of the leaf and ripped the front leaf spring mount out of place. In that process the seat belt (mounted to that leaf spring mount) must have been damaged. I think it was replaced with a B-body belt but not sure. As I said I had to modify that passenger belt to fit and work close to the e-body one.
If you look closer at this pic you can see the mod on the rear recoil unit. There is a similar mod on the outside of the front one. The cases I got from another set I picked up at Carlisle few years back. Mechanisms on that set rusted to crap. This set works.
Note also the wired buckles - part of the '74 seat belt warning system.

[72 Challenger]

A few squirts of spray and wash, let it soak for a day and then I put mine in a couple of pillow cases and ran them through the washing machine.

Does your wife know you did that ? 

I work from home during the day while she is at work. What she does not know will not kill her! I have been known to clean an intake or two in the dishwasher too. 

[usraptor]

I soaked mine in Wool lite.  Then scrubbed with a stiff bristle brush.  I used steel wool on the metal and painted the plastic with SEM black Landau.  They came out looking almost new.