You could look into getting it professionally cleaned and conserved. I don't know the price, but it would be worth looking into for your photo.
I'm not a condition freak and am ordinarily for leaving items as is, but this is an exception-- if that's what you want to do. There's nothing unethical about restoration-- and it can be a good thing if the item is falling apart of deteriorating--, so long as the restoration is disclosed at sale.
I wrote a short piece on the issues and ethics of restoration at the end of this
SABR post