When Al goes into the kitchen to sneak the sandwich, and Tim catches him, he pretends to be drinking a glass of water. He frantically fills a glass, and holds it up to show Tim, showing it has only a few drops in it. In the next shot, the glass is full.
When the hot rod is in the garage and filled with snow, one of the doors is opened facing the camera and the plastic protecting the interior can be seen.
Jill moves Tim's hot rod convertible outside, where it gets thoroughly covered by snow in a blizzard. We later see the car inside the garage and the interior is completely filled with snow. How did Jill get the car back inside the garage? She couldn't have driven it and even if she got the boys to help her push it, the interior would still need to be cleared of snow to put the car in/out of gear.