House Call - S5-E13
Trivia: The house used as Katrina's residence was also used in season 8 of Beverly Hills, 90210 as Carly Reynolds' house.
Ms. Hellfire - S2-E9
Trivia: The stricken names from Ms. Hellfire's hit list are all names of Charmed crew members.
Trivia: Between seasons four and five, Rose McGowan had dyed her hair red in order to play Ann-Margret in a TV biopic about Elvis Presley. The issue of Paige's hair color was explained as a goof-up while mixing potions.
Trivia: Chris' role this season (specifically, his traveling to the past from the future) was originally intended for Wyatt. After deciding that Wyatt coming back from the future is what viewers would expect, Chris was created and introduced instead.
She's a Man, Baby, a Man! - S2-E5
Trivia: When Prue is turned into a man, her look was partially inspired by Shannen Doherty's boyfriend.
Trivia: Christine Rose, who plays Prue's boss Claire, played Holly Marie Combs' mother on Picket Fences.
Trivia: Although it was never intended, this episode served as the inspiration for Mermaid, the pilot of a spin-off series. The pilot was produced concurrently with "Something Wicca This Way Goes", but was never picked up.
Extreme Makeover: World Edition - S7-E12
Trivia: When the demon "in a bad suit" hurls a fireball Piper vanquishes him, and in the next shot that fireball hits the building across the street. Note this is the Bay Mirror where Phoebe works, but the newspaper's plaque has been removed from the doorway. (00:26:10)
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.