Whitening when the usual methods are not an option?

[WeepingPiano]

I promise I did do a cursory search of the forum.

If submerging the pony in Hydrogen Peroxide or using Zit Cream is not really feasible, what is the next best way to whiten a white pony that has yellowed?

I tried typing in "whitening" but just got the hydrogen peroxide treatment.

[Safflower]

Sunfading is the most common method of whitening a pony. Basically, you just cover the paint and hair and leave the pony out in the sun, though there are a few who burn. Who are you planning on whitening?

NEVER use acne cream. It can severely discolor a pony and that discoloration can spread to other ponies if they come in contact.

[LadyMoondancer]

Which white pony is it?  Some white pony will "burn" (tan) in the sun.  For example:  Starshine, Gingerbread, and Cherry Treat.

[lovesbabysquirmy]

1) Depends on who you are trying to whiten
2) Sometimes there is nothing you can do

We need more info to help you!

[mlp4me]

A picture is always helpful in diagnosis and then if treatment is an option, we can suggest some next steps. Sometimes browning can be from "cancer" which is alas, incurable....

[WeepingPiano]

I will try to get some pictures up soon, but I have a giant project pony blank that has some yellowing on the neck and around an eye. Kept in a dark room in a non-smaoking home and all that. It is also Winter where I am, so not real sure about sunfading...

I would like to clean it up a bit before I sell it...

[Ringlets]

If it's not a scented white pony then sunfading is usually the best way to whiten it.  There are only a few ponies where sunfading is a bad idea (as mentioned Cherry Treats is definitely one of them. I've successfully faded a Gingerbread without her going brown though)
 I have more experience with sunfading G1's to be honest, but it's probably worth a try with your pony. Just make sure you keep checking on it regularly. BTW , you don't need it to be sunny to sun fade your pony. Any natural daylight will do it, so in a window that gets plenty of natural light ,  even in winter. (I'm in the UK... we don't get much actual  sun usually!!   )