If any sticky substance which is impure, such as oil, ghee, the fat of a dead animal, gets stuck to something and is washed until clear water begins to flow, it will be purified even if the stickyness of that impurity remains.
Some impurity falls into pure water. By its falling, the water splashes and a few drops fall on someone. These drops are pure on condition that there are no traces of that impurity on the person.
If a cloth having two folds or a cloth that is filled with cotton (such as duvets) becomes impure on one side and is pure on the other side, then the whole cloth will be regarded as impure and salaat on it will not be permissible. This is only if the impure area of the impure side is the area on which the musalli will stand or prostrate. Another condition is that both the cloths must be sewn together.
If they are not stitched together, then impurity on one side will not render the other side impure. In fact, salaat will be permissible on the pure side on condition that the cloth is so thick that the traces and smell of the impurity underneath do not come on.
If a chicken or any other bird is boiled in water before its stomach, intestines and other filth can be removed, as is the custom today, it can in no way be regarded as pure.