Usage patterns
〈場所〉に残り物があるthere are leftovers in/at a place
There are leftovers in the fridge.
残り物で〈物〉を作るto make something out of leftovers
I made curry out of leftovers.
残り物を片付けるto finish off/clear away the leftovers
I cleared away the leftovers from dinner.
残り物を温めるto reheat leftovers
I reheated yesterday's leftovers and ate them.
Expressions
残り物に福ありthere is unexpected good in what others have left behind; last but not least; there is fortune in leftovers
