What are considered repulsive things? Is skin oil among them? Does a repulsive thing transmit its repulsiveness just as impurity is transmitted? And does water become repulsive if something repulsive falls into it?

It has been previously explained that the criterion for impure things (mustaqadharat) is custom (urf). Skin oils are not necessarily impure in all cases, for the soul may dislike something from one aspect but not another. Furthermore, it is not necessary to apply the rulings concerning the transfer of impurities (najāsāt) to the transfer of impure things (mustaqadharat). The falling of an impure thing into water does not necessarily render it impure in all cases; rather, it depends on its effect on the water, and this too is referred back to custom (urf).