Can I dye or bleach a duvet cover?

Bedding that contains cotton, linen or polyester is the best candidate for receiving and holding dye. Cotton or linen bedding absorbs the full intensity of the dye, and polyester or polyester blends usually achieve a lighter shade of the dye's color. Silk bedding requires a specialty dye, often called hand fabric dye. Most 100-percent synthetic materials will not accept dyes available from craft stores or drugstores.

You can use a color remover from Rit Dye to remove color. To dye a synthetic fabric you can use Rit Dye's newer Dye More product but dyeing will only darken it if you don't use the color remover first.

It depends on the material it's made of. You can dye synthetic fabrics but you need specific dyes for those. If it's all cotton then yes, dye will work. Bleach may damage and weaken the fibers.