Message: I have country blue thermal backed curtains that are 56% cotton, 44% polyester. I would really like to dye them a more neutral color like tan or taupe. My couch is olive green so they could even have a slight greenish tint if need be. Can you tell me if it is possible to dye blue to a more neutral color and if so, what color and brand might be best? Thank you for your help.

Blue is a darker color than tan. Dyes are transparent and can only add color, not remove it. It is impossible to bleach polyester, as it is permanently damaged by contact with bleach, so you will not be able to lighten the color before dyeing.

It would not be too difficult to add a greenish color to the cotton portion of the fiber in your curtains. I think that overdyeing your curtains with a yellowish brown might meet your needs, turning your curtains more of an olive green. The results might be darker than you like, however.

No easy-to-use dye will color the polyester in your curtains, but the cotton can be dyed with either fiber reactive dye or all-purpose dye. All-purpose dye is not noted for its washfastness (a little bit will bleed in every laundering), but it is easy to find and should meet your needs. You must use HOT water with all-purpose dye. If you wish to dye at room temperature or with merely warm water, you must buy some fiber reactive dye, such as Procion MX type dye; this can be mail ordered from many of the companies listed on my "Sources for Dye Supplies" page.