We’ll give you just a few reasons why that’s happening. Yellowish stains are typically from sweat and body grime. However, orange-ish discolorations are chemical reactions. These chemical reactions can be caused by: Wearing your hat post-swim. Your hair will still be holding chlorine and other pool chemicals and they’ll slowly turn your hat orange. Facial products. Lotions, facial treatments (especially benzoyl peroxide!), and other creams will turn your hat orange. Haircare products. Same reasons as above. Discoloration usually happens when sweat and chemicals sit on the hat for long periods of time. So if you rinse them off right away and wash them, it might minimize the discoloration. Lastly, discoloration of black happens because there's no such dye color as 'black' in the natural (cotton, wood, etc) world. Sun and washing machines will beat the darkness out of anything over time.