How to remove yellow staining on metal sliding doors

[wingers999]

How to remove yellow staining on metal sliding doors

I think it has perhaps been caused by sun, as it is on the two doors nearest window and lines up with sun coming in down side of curtain perhaps

Tried bleach, vinegar, barkeepers friend and more, nothing works

Looks a mess and next option may be to cover them or paint them

Any thoughts please

They dont look metal in the picture

But this is amazing on amazon 3x Autosol Metal Polish Chrome Shine Metal Polish Chrome Polish 75 ml

the doors are definitely metal, the coating / paint layer on top may be something else, but definitely metal sliding doors, perhaps some sort of enamel painted layer on top? Thanks will take a look