Possible Clues:

• Mucking out the pigs, e.g.
• Do the __
• Disagreeable, tedious tasks
• Dishonest practice in operation of sweep, say
• Unpleasant tasks
• Skulduggery? I'd try fresh employment
• Dishonourable dealings - need bath afterwards
• Dishonourable dealings or unclean labour
• For example, what makes a clean sweep unlikely? Foul play
• Nefarious activities producing obscene publication