Ritual Impurity in the Torah
Question
In the Torah, specifically Leviticus, you will have contagiously unclean people. I'm wondering, if they sit on a seat that becomes unclean, how does the seat become clean again? Is it similar to earthenware, in that it can just be washed? Or is there a different purification ritual to clean the seat? Or is it only unclean for as long as the original unclean person is unclean?