During the food fight, Piper has orange jelly smeared on her hands before she picks the jelly up.
There are very noticeable stand-ins used during mot of the food fight scene.
Obvious stunt doubles for all the principal actors when Leo gets blasted across the attic by Wyatt.
This aired in January and the characters are shown wearing winter clothing. However, it's stated on the Halliwell family tree that Piper's birthday is August 7th, 1973. So everyone should be in summer attire rather than winter gear.