Sayyidah Duba'ah bint al-Zubayr (may Allah be pleased with her) - who was married to Sayyiduna al-Miqdad - said: People used to go to relieve themselves only every two or three days, and they would pass droppings like camels do. One day Sayyiduna al-Miqdad went out to relieve himself until he reached al-Khabkhabah - which is in Baqi' al-Gharqad - and he entered a ruin to relieve himself. While he was sitting, a rat brought out a dinar from a hole, and it kept bringing out one dinar after another until there were seventeen dinars. (Al-Miqdad (may Allah be pleased with him) said:) I took them and came to the Messenger of Allah (peace and blessings be upon him) and told him (peace and blessings be upon him) about them, and he (peace and blessings be upon him) said: "Did your hand reach into the hole?" I said: "No, by the One who sent you with the truth." He (peace and blessings be upon him) said: "There is no charity (sadaqah) due from you on it; may Allah bless it for you." Duba'ah (may Allah be pleased with her) said: "The last of it had not yet been used up before I saw silver bracelets in al-Miqdad's house."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17745