It is, in appliance years, an antique. Appreciate it for the natural patina just as you would not refinish and ruin any other antique. Enjoy your find!

If you can remove the covers on them, you can spray paint with paint made for plastic, like Krylon. Or if you have to leave in place, they have a brush on paint for plastic:
https://www.krylon.com/press-room/press-releases/2011/04/krylon-introduces-the-first-brush-on-paint-for-plastic/

You can try some creme peroxide (the kind used for lightening hair). It may bleach it back to white. Just paint it on and cover with plastic wrap. Do NOT get any one the inside...

Are they plastic or metal?..posting a picture up close and further back that shows where they are....may provoke new suggestions as well...

We took the covers off of ours and spray painted them white.