Is there anything you can do to restore the color of faded clothes?

Question

Maybe a detergent or something?

Answer 1

Some detergents have brighteners, but they don't restore color, they just make the fabric "brighter" through microscopic prisms.  

I urge caution about trying to redye fabric.  All the misc stains, sweat spots, etc that apparently washed out have still left a tiny residue which shows up immediately when you attempt to redye something.

Answer 2

None other than dying but that's a gamble.  I practice trying to keep the color from fading by using only a little detergent in my wash, I mean after all, how dirty are they really?  I also add one scope of oxygen cleaner to my wash to keep my colors looking brighter and my whites whiter w/out using bleach which will weaken the fabric.

Answer 3

No, not besides dying. I'm thinking of the black cotton that fades so fast. You can keep the color bright a litter longer in the first place by a soak in vinegar which acts as a mordant. (This will also color fast after dying an item, but I would still wash seperately to be safe).