How to fix cloudy/hazy black paint after using toothpaste to buff out minor scratches?

Toothpaste might work on dull headlight lenses but not on paint, now you have badly scratched the clear coat and if you went too deep into the base coat itself. The only thing you can do yourself is get some Mothers swirl remover and see if that works, if it don't then you either try using some Black car wax on the vehicle or leave it to a professional detailer.

Toothpaste belongs in your mouth and not on your car. Polishing compound with a very light cut or as tennisshoes suggested.

After a family member drove my pride and joy into the iron maiden of thorny tree branches, and left multiple nose-to-tail stripes down the passenger side, I was desperate for a solution. I saw enough people suggesting toothpaste, so I thought I would try my luck. Like Susanna, I was left with some cloudy swirl marks where I had gotten a bit too eager. I read Bob's suggestion about a light cut polish. I spent $10 on an ArmorAll cream cut & polish, and a few hours polishing the entire side of the vehicle. The scratches are NOT 100% gone. But they are 50-75% less visible, enough where if you didn't know where they were, you don't see them. The swirl marks ARE 100% gone, absolutely no trace. So was toothpaste the best option for a total fix? No, there are other methods that will yield better results. But a $4 tube of Crest whitening, a $10 jar of polish, a $2 roll of paper towel, and a few hours of my time was a lot more affordable than dropping $100s or even $1,000s on professionals to sand down all those scratches on 2 quarter panels and 2 doors, repaint the metallic ironbark, and reapply the clear coat.