Is the Maliki and Hanbali Schools’ consideration of minor dirt under the fingernail as a pardoned barrier absolute, or only in cases where its removal would be difficult? And if it is discovered before prayer, and one is able to remove it, is its removal obligatory? And does this ruling apply specifically to dirt and things that are not greasy, or to all types of dirt? And what is the ruling on a thorn under the skin – is it considered a barrier?