Pick up the mop without holding down the mouse button
You can pick up the mop and actually hold it without holding down the mouse button.
First grab the mop using left click and hold it. Then right click as you’re holding down left click. A menu should pop up. Then let go of left click and left click on the mop again. You should be able to hold it.
This is useful in the later stages when all you’re doing is cleaning up. Just place the mop on one of the spill spots, relax and let the game rake in points for ya. Just keep the volume up though so you can hear any demanding petpets. – Thang