Is it obligatory to wash all of one's clothes, or is it sufficient to wash only the area of janabah?

According to the preponderant view among scholars, semen is pure. It is only recommended to wash away its trace if it is wet, based on the hadith of Aisha (may Allah be pleased with her) that she used to wash it from the garment of the رسول الله (Prophet Muhammad) (peace be upon him). If it is dry, it suffices to rub it off with the hand, and its trace does no harm, based on the hadith of Aisha (may Allah be pleased with her) that she used to rub it off from the garment of the رسول الله (Prophet Muhammad) (peace be upon him) and he would pray in it.