Of course! Here are some projects to help you with it! https://www.hometalk.com/14546041/diy-spray-painted-doorknobs-ugly-brass-to-beautiful-oil-rubbed-bronze

DIY Spray Painted Doorknobs: Ugly Brass to Beautiful Oil Rubbed Bronze

Yes, you can paint them. Just make sure you clean them well before painting them and use multiple coats. I've used this type of paint on mine and they are holding up well: https://amzn.to/2Ds57TZ

Hope this Helps! Jeremy - https://do-daddy.com

Yes you can paint them but I'd remove them first and use a good quality spray paint so you get an even finish. I repainted my bathroom light and it looks beautiful now... https://www.girljustdiy.com/bathroom-light-makeover/

Sure ! Use two light coats of spray paint instead of one heavier coat !

Yes you can. Indoor or outdoor?

I asked the same question to Rustoleum- my knob oil rubbed bronze finish had both worn away and faded outside and they recommended their universal spray paint line.

Their comments:

Our Universal line of sprays are great for exterior surfaces and it does offer an oil-rubbed bronze color in the metallic line if looking to stay with the same finish. You will want to ensure that the surface is clean and lightly sanded to create a surface profile.

https://www.rustoleum.com/product-catalog/consumer-brands/universal/universal-metallic-spray-paint

If possible, it will be best to remove the hardware, so that it will be easier to spray and you won't need to mask off the whole door. The keyhole can also be plugged to prevent issues once it dries.

You can spray paint them but eventually the paint will wear away. You might try a trick of boiling them with baking soda. You can see what I did here: https://www.flippingtheflip.com/2015/05/where-are-you-so-its-mini-variety-pack.html