mop–up 
/ˈmɑ:pˌʌp/ noun
/ˈmɑ:pˌʌp/ noun [singular] informal : the actions that complete a job or task after the more difficult parts have been done
▪ The project is almost done. All that's left is the mop-up. — often used before another noun ▪ mop-up duty ▪ the mop-up phase of operations — see also mop up at 2mop
▪ The project is almost done. All that's left is the mop-up. — often used before another noun ▪ mop-up duty ▪ the mop-up phase of operations — see also mop up at 2mop
