Just read through the thread link Goktimus provided below - that is the ongoing thread we have here in the forum.

Soaking time for the figure varies. you just have to keep monitoring it but usually it takes days. unless you use industrial strength concentration

The creme developer I use - available on stores where they sell haircare products - it' sused for bleaching hair to blond color - is 12% in strength.

The advantage of the creme is that you don't need to disassemble the parts you need whitened just paint it using a big cotton buds. usually it takes still days (varies) for the effect to start. So, you gotta keep observing it. Wipe off the first coat once it's dried out a bit before adding a new coat.