Ideas to restore this parts

https://preview.redd.it/8iyuvshh70eg1.jpg?width=4000&format=pjpg&auto=webp&s=6c49d5654fb7e4ad92d13eb4f8b759257183b119 Pretty much as the title states, I got almost 2 full sets of the 8880-1 Supercar/F1 Car for £20, the white parts are pretty sun bleached. I washed them and then let them soak in a fairly weak bleach solution, around 10:1 water and bleach, it did brighten up some of it. But there are obviously some that it barely did anything to. I'm hoping for some ideas to get them restored...