Meaning: Resolve a problem
Example: He was left to MOP UP the mess after they resigned.
Meaning: Kill or capture the last few enemy soldiers after a victory.
Example: After the battle, it took them a couple of weeks to MOP UP the remaining rebels.
Meaning: Eat a sauce with bread to finish it
Example: The sauce was so delicious that I ordered some bread to MOP it UP.
Meaning: Remove a liquid that has been spilt
Example: I used a cloth to MOP UP the coffee I had knocked over.