The most common reason for strange orange or light-colored marks on towels is a chemical called benzoyl peroxide. It’s a popular acne-fighting ingredient found in many products such as PanOxyl, Clearasil, Neutrogena, and some prescription creams. While it works well on skin, it is also a strong oxidizing agent—meaning it can act a lot like bleach when it touches fabric.

On dark towels like black, navy, or charcoal, the bleaching process often turns the fabric orange, yellow, or even pink. That happens because the darker pigments in the dye are destroyed first, leaving behind lighter base tones. A simple way to tell the difference is this: if the mark is lighter than the towel, it’s likely bleaching. If it’s darker, it’s probably a regular stain.

These spots will not wash out because the dye has already been removed from the fibers. No detergent or scrubbing can restore color that’s been chemically stripped away. In some cases, washing affected towels with other laundry can even spread leftover residue and damage additional items. Although benzoyl peroxide is responsible most of the time, other causes exist.

Rust from old pipes can leave reddish-brown streaks, and a bathroom bacteria called Serratia marcescens can create a pinkish film—but that usually wipes away with cleaning. To prevent damage, use white towels for your face, rinse thoroughly after acne products, or switch to alternatives like salicylic acid. Ruined towels can still be repurposed as cleaning rags or gym towels.