Scholars have differed whether washing ears in wudu‘ is obligatory or recommended. Therefore, a Muslim is recommended to be keen to wash his or her ears properly in wudu‘ so as not miss the merits of following the Sunnah.
However, in case of obligatory ghusl, water should reach all parts of the body. Therefore, if the earrings worn by women prevent water from washing the ear, they should be removed, as water has to run over every part of the body without prevention.