These San Diego classic khaki caps are super easy to use. Just put them on your head and you're ready to go! They're great for outdoor activities, casual outings, or just to add a stylish touch to your look. As for the warning about chemicals, don't worry too much but be aware. When it comes to maintenance, you can gently hand - wash them with mild detergent in cold water. Avoid using bleach or harsh chemicals. After washing, let them air dry. Don't put them in the dryer as it might damage the shape of the caps. And that's all you need to know to make the most of these caps!