Peroxide! I’ve tried bleach, but not H202! Thanks!
I’ve done the main bearing, but not the idler. The wheel only has two hairline cracks, it’s been in a favorable climate for 50years. I did the rejuvenator thing.
With bleach, don't forget the time element. If it soaks a while, it will be much more effective than wiping it with a dampened cloth. I spent a couple days bleaching a mid century modern dining set, with molded fibreglass chairs which were badly stained, and it came out beautiful. Results were far from instant though, I had bleach soaked rags in contact with the stains for hours, and kept coming back and adding more as it evaporated.