Ganga & dog - Sanskrit maxim

Courtesy:Sri.Shankara

का क्षतिरम्ब कटाक्षे न्यस्ते सति मयि विरिञ्चिवरपत्नि ।  गङ्गाशुनकन्यायान्महती मम वृद्धिरीरिता निपुणैः ॥ २४७॥

https://sanskritdocuments.org/doc_devii/shAradA300.html?lang=sa

When the holy waters of Ganga come into contact with a dog, the waters are not polluted. On the other hand the dog gets rid of all its pollutions and impurities.