The Cleaner

 is a miscellaneous quest in Fallout 4.

Quick walkthrough

 * 1) Buy an alcoholic drink from Whitechapel Charlie.
 * 2) Accept the quest from the ensuing conversation.
 * 3) Go to the  all 3 Goodneighbor warehouses. Kill all enemies inside.
 * 4) Return to Whitechapel Charlie to collect the reward.

Detailed walkthrough

 * 1) Enter into The Third Rail in Goodneighbor and find Whitechapel Charlie.
 * 2) Purchase an alcoholic drink from Whitechapel Charlie. He will initiate a conversation with the player about needing someone for a job. The job is to kill the men inside the Goodneighbor warehouses.
 * 3) (optional) Persuasion check for more caps reward.
 * 4) Accept the quest.
 * 5) Navigate through Goodneighbor to find the 3 warehouses. Their doors will be locked and each requires a bobby pin to lockpick them.
 * 6) After gaining entry into the warehouses, kill the enemies residing inside.
 * 7) Return to Whitechapel Charlie for a reward of 200 caps (or more if you passed the persuasion checks).

Behind the scenes
The quest's name is like the quests for Fallout and Fallout 2.