How to help a yellowed Quackers

[Starbright]

Hi all! After nearly 10 years away from collecting, I've been getting back into things and pulling my collection from storage.

Unfortunately, I found my twinkle eye Quackers and Baby Quackers have both yellowed while in storage.

I have been reading about the options to try and help whiten them again. I see that sunfading often "burns" Quackers, and while hydrogen peroxide might work, I would need to be careful and keep her hair out of the peroxide because it would fade it. It would also damage her eyes.

Has anyone ever tried the trick of covering a twinkle eye pony's eyes and symbol with acrylic craft paint before doing a hydrogen peroxide soak, the way people do for protecting paint while sunfading? Would it protect the eyes and symbol, or just wash off in the soak?

Has anyone ever done a hydrogen peroxide soak specifically on a Quackers or Baby Quackers?

Has anyone found any method that does work on whitening a Quackers or Baby Quackers without causing damage?

[tailrustedtealeaf]

I have a feeling that the acrylic paint would either come off in the soak, or not protect it fully. It is not a waterproof barrier.

[mlp4me]

I've been soaking a project in H202, then just water with very extremely think acrylic paint over symbols. 2 weeks later acrylic has only slightly bubbled and spread into water. You could try for the sake of science... at least neither is super rare. If you have brown cancer spots with a dark center then It's too late I fear.

[LadyAmalthea]

Following in case someone has a solution to this...I have a Baby Quackers that isn't exactly yellowed, but seems to have a gray, dirty look to her, and I just had the feeling that sun fading would be bad for her. Not sure why some white ponies seem to be made out of different plastic than others. I'm going to try some things, whitening toothpaste, baking soda, oxyclean, etc. and I'll let you know if anything helps.

[SunPony]

I'll be following along, too, I've got a baby Quackers with a reddish path on his/her chest and I'm not sure what to do about it. 

I never heard that hydrogen peroxide harms the eyes before.  I know I've seen images somewhere of ponies soaking in H202 with their symbols/eyes uncovered.  Now I'm not sure what to think...