Want to help clean up?

After inspecting Number 12, Grimmauld Place, Mrs. Weasley said in a somewhat grave tone, "Getting this place properly cleaned won't be easy!"

"I had Kreacher sweep away all the dust..." Sirius Black said, sounding puzzled. "What's left should just be Doxies and things... right?"

"Yes, they do seem to be Doxies." Mrs. Weasley nodded, then changed tack. "But we need to find their nests and clear those out too..."

"That's the most important part! They're incredibly tenacious. If they aren't completely cleared out, the new Doxies will be flying everywhere again within a week at most."

Mrs. Weasley had kept The Burrow in perfect order all by herself, so she could naturally be considered an authority when it came to assessing matters like this. No one argued with her.

Those magical cleaning agents Hannah had brought were indeed past their expiration date, but thrifty and resourceful as Mrs. Weasley was, she still found a way to put them to use.

"Neville, Hannah, take these magical cleaning agents to the third floor..." she said, looking at Neville and Hannah. "Turn right, then go to the room at the very end..."

"That's a potions room, and it's full of Hairy Crabs..." She pointed at the large bag in Hannah's hands. "Pour all of this into the cauldrons. It should deal with most of the Hairy Crabs."

"The remaining Hairy Crabs are easy enough to handle. Just stomp on them. Remember to put some force into it, or they might jump up and chew off your wand."

"Then look around that room for their nests..." As she spoke, she took a book from the pocket in front of her.

Wizet found the image on the book's cover strangely familiar. It was unmistakably one of Gilderoy Lockhart's works: *Gilderoy Lockhart's Guide to Household Pest