Scum - Better, rust (and in Ezekiel 24:11-12).
Bring it out piece by piece - It, the city; bring out the inhabitants, one by one, clear the city of them, whether by death, exile, or captivity.
Let no lot fall upon it - In the captivity of Jehoiakim and in that of Jehoiachin, some were taken, others left. Now all shall be removed.