Have you tried coating them with ACF 50 or something Jo? I polished all bare metal parts (spokes etc) with autosol metal polish when the bike was new, but couldn't find ACF here but coated all with this...

Everything is still as new now over a year later. Living near a coast here bare metal can go rusty quick to if left alone.
I have also coated the rims & hubs with this stuff, they are still looking good too.