Just be careful what you ultimately use. Some of the products mentioned here are safe for some applications but not others. In particular, you want to be sure to use something that is color-safe. A chemical that works great to make white linens whiter may also bleach out colors. Also, a product which is "safe" for an hour may cause color loss in cotton fabric if soaked overnight. A product which takes out a stain may also weaken the fibers. I would strongly advise thoroughly researching on the internet before deciding to use any particular product on a finished quilt.
Even the sun is not necessarily safe, even though it is natural. Colors in cotton fabrics fade with exposure to light, including sunlight. Colorfastness in fabrics is "tested" by how many hours it can tolerate exposure to light without visible fading. For most fabrics, I think it's only 75 hours. If you want a quilt's colors to last for a generation or more, you want to limit exposure to light -- including direct sunlight and indirect sunlight. Even indoor lighting causes fading, although much more gradually. While some fading is normal "patina" -- as in vintage quilts in which the colors have faded slowly over time -- there is no need to rush the process by producing several years of fading in a single day.