What is the difference between tangible impurity ('aynīyah) and intangible impurity (ḥukmīyah), and what are examples of each?

Scholars have differed on the definition of aynīyah (tangible) and hukmīyah (legal/intangible) impurities. The majority defined aynīyah as an impurity that has a taste, smell, color, or touch, and hukmīyah as that which has no taste, color, or smell, like urine that has dried and aged. As for the Hanbalis, they defined hukmīyah as an impurity that occurs on a pure place, and aynīyah as inherently impure substances like urine, which can never be purified. The Malikis held that aynīyah impurity is removed by any cleanser other than water, while both hukmīyah and aynīyah impurities are removed together by pure (absolute) water.