Everything he said.Just wash them. They're cotton so they will look ugly after a couple uses. Doesn't affect them. Keep pads moist or damp by putting them in a trash bag or tote after use. Dont allow them to dry while dirty.
I wash cotton on hot and use oxi clean, wash soda or similar whatevers around. Then set machine for extra rinse. Absolutely do not ever use fabric softener liquid or sheets ever on bonnets.