How can I paint the knobs on cabinets and doors?

You can spray paint, Bonnie. You can use Kilz spray primer, let it dry then spray with clear laquer to make more scratch resistant.

We just spray painted all of our knobs and handles in the kitchen! Make sure to use a good primer first, And just like above, a good top coat is important so the paint doesn't chip off. It is a tedious job, but will save you money

Yes, we just did this with great results using a Rustoleum spray paint. We painted old brass to white and chrome to off white. The paint contained a primer, so we did not prime and so far, so good!

rustelouem has a great spray paint to change the color of hardware on cabinets as well as door knobs

https://www.youtube.com/watch?v=3tPRndlllFA

https://www.hometalk.com/diy/paint/furniture/how-i-spray-paint-hardware-1121619

https://www.hometalk.com/diy/paint/furniture/updating-hardware-with-spray-paint-32851250

https://www.hometalk.com/diy/craft/wreaths/how-to-paint-hardware-for-a-durable-finish-8160709