painting seat belts

FWIW..
I used this stuff on my carpet and got "good enough for who it's for" results.
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Not like new but it didn't stiffen the carpet at all. Not sure how it might (or might not) work on belts. The "New" is excess cut from the replaced floor carpet.
auto carpet dye

I covered my pool table slate recently after finally reassembling, going from blue green felt to green. Thought I'd try this fabric spray (Hobby Lobby) on the faded bumpers...…
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The spray did stiffen them up some. Brushing helped loosen the felt a bit.