RavenMileyandAFVRock was kind enough to upload it onto YouTube.
Why was this cut? Some people said that it was because this was a form of "sneaky terrorism." Another explanation, and the most likely one, is that it was because it would show children that gasoline + fire = boom, and the people were afraid of kids playing with explosives.
This wasn't the only deleted scene; Procrastination had a few. In the first one, SpongeBob is just beginning to write his essay when he looks out the window. The sun is smiling, Squidward's tanning, kids are playing, the Jellyfish are having a rousing game of tennis. Among the frolic and happiness was Patrick rubbing sunscreen on Sandy, which is why it was removed.
The second removed scene on Procrastination was where SpongeBob comments that he has to get his essay done so he'll be one step closer to earning his license. Cut away to a live-action dragster driving off and flipping over.
Last, and definitely not least, at the end of The Secret Box, during its first airings...we got to see the embarrassing snapshot of SpongeBob at the Christmas party! ...Or so I heard, anyway. If anyone could confirm this information, or has a video of any of these scenes, please comment.
I think a bit of the smiling-sun-playing-kids scene from Procrastination could be seen in the Best Day Ever music video.