How do I clean/polish these door handles?

Hi! I would warm up some vinegar and scrub them with 0000 steel wool and warm vinegar. That will brighten them up! And clean them!

This pin for sure will help you :) https://www.pinterest.com/pin/549228117058845036/

Maybe try using Young Living's Thieves cleaner. We use that for everything in our home

When I need to clean up hardware I use my crock pot. Fill with water, add a few squirts of Dawn and the hardware. Let it "cook" on high for at least 6 hours or as much as overnight (the time depends on how dirty or many coats of paint is on this). The paint should peel right off and these look new.

This is how I cleaned my metal hinges. Whatever you try, I would test it on the back of the doorknobs first to be safe.

If you can't clean it well, you can try sandblasting it then polishing.

If you can’t get them clean, you could try spray painting them.

This is a tutorial for spray painting them: https://www.rustoleum.com/project-catalog/color-watch/satin-bronze-hardware/

Get brasso cream cleaner and clean them up

I'm assuming you do not want to remove the door handles. So I would first try using WD-40. It's amazing what it can do. If it doesn't work, no harm done. Apply WD-40 to a small soft cloth and clean the handles well. In the very intricate areas you could use q-tips. Let set for a few minutes then polish well with a soft dry cloth.

https://www.familyhandyman.com/smart-homeowner/20-brilliant-ways-to-use-wd-40/

Maas metal cleaner.

Hi Druzon, hope this helps, you want to give them a good cleaning first, then try this trick

https://www.instructables.com/Cleaning-Badly-Tarnished-Brass-Bronze-and-Silver/

If you take them off, put cream of tartar powder in a large soup pot and boil for several hours. Let sit overnight and rinse off. Or just clean them with dawn let dry and use Rustoleum primer. Let dry completely and then use Rustoleum Metallic spray paint. It last for years.

If you can remove them, you can use toilet bowl cleaner; either by brushing it on or dipping them in it. Watch it, though, as it is corrosive and can take 'cleaning' too far. ;/