Visible impurity is purified by removal of its substance with any purifying liquid that removes it—such as vinegar, rose-water, used water; a trace difficult to remove is overlooked.
تحفة الملوكZayn al-Dīn al-Rāzīفصل في إزالة النجاسة
Chapter on removing impurity
Non-visible [impurity] is purified by washing that preponderantly removes it.
Everything smooth—mirror, sword, knife, and the like—is purified by wiping.
والمَنِيّ نجسٌ يَجِب غسله رطباً ويكفي فركه يابساً.
Semen is impure; washing it when wet is obligatory, and rubbing it when dry suffices.
ولو ذهب أثر النجاسة عن الأرض بالشمس، جازت الصلاة على مكانها، دون التيمّم منه.
If the trace of impurity leaves the ground by the sun, prayer on that place is permitted, not tayammum from it.
وإذا أصابت الخفَّ أو النعلَ نجاسةٌ لها جِرمٌ فجفت فدلكه بالأرض، يطهر بخلاف المائعة والثوب.
If impurity with body [to it] strikes the sock or sandal, then it dries and he rubs it on the ground, it is purified—unlike liquid impurity and clothing.