Muggles' Guide to Harry Potter/Magic/Tergeo

Overview
One of a number of cleaning charms, Tergeo seems to siphon fluids or dust off a surface.

Extended Description
In Harry Potter and the Half-Blood Prince, Hermione uses this spell to remove blood from Harry's robes; later, she uses it to clean spilled ink off Ron's Dementor essay.

In Harry Potter and the Deathly Hallows, Ron uses this to clean grease off a rag which he then gives to Hermione to wipe her eyes with, and later Harry uses this spell to clean dust off pictures that he finds in Bathilda Bagshot's house.

This charm seems to be related in effect to Evanesco and Scourgify.