Last weekend, after my first-ever adventure to the phenomenon that is IKEA, I found myself with two too-light and too-bright couch pillows. I loved the Jacobean-like embroidery covering the front, but the colors were just as bad in my living room as I expected them to be.
First, take the covers off of the down pillow forms, then soak them in some RIT color remover.
Finally, give them a bath in RIT tan dye, which mellowed them quite nicely.
the same cushion on IKEA's website.