I do pretty much the same thing.
I might try some sportwash from walmart. I remember reading about it when it first came out. They claim that (most) camo fabrics these days are being produced from China,Taiwan,Etc. and that they add UV brighteners to it. Sportwash is supposed to neutralize the UV brighteners(the same kind that's in laundry soap). I remember the advertisement showed 2 guys in treestands. 1 with camo that was treated with sportwash and 1 without. The guy with untreated camo looked like a big blue blob.