A warm vintage-style winter cap with ear flaps keeps you warm yet fits under your helmet easily.
Wash whites and dark colors separately in cold water.
Wash inside out and zipped up.
Do not tumble dry. Hang and dry instead.
Do not bleach, dry clean or iron.
Do not use softeners, washing powders and avoid big commercial detergents.
Do use enzyme-free detergents like Seventh Generation, Trader Joes or LeBlanc.