Yesterday I bought some H2O2 and have been using cotton tips to rub it into parts of my Fortress Maximus, especially the right upper leg section. I'm not sure if I'm seeing whitening or if it's my imagination.

I can't be bothered disassembling the toy to soak the pieces in an H2O2 bath... but one thing I'm not doing is letting it set in sunlight (but one fear is that, because I'm not coating the entire toy in one go, it might yellow the uncoated parts even more).
So, short of doing the H2O2 bath thing (ceeeebs), should I:
* Put the toy in direct sunlight anyway
* Avoid sunlight, but just keep applying more H2O2
* Or maybe expose the toy to "mild UV", i.e. open the blinds in my TF room (the window faces east, so the western sunlight would be bouncing off opposite buildings and back into the window - so it would be indirect sunlight coming in)?
I guess what I want to know is... is applying H2O2 onto the toy still useful for whitening if it's not being exposed to sunlight (but perhaps less effectual), or is it a complete act of futility? I've only been rubbing the H2O2 in the right upper leg, none of the left. I'll take a photo this evening and post it to see if anyone else can notice any difference between the two sides. I've done about 5 applications so far since yesterday afternoon.