There is a mistake in this episode. When Squid Ward tries to find a way to apologize to Sponge Bob, he puts a message in a bottle. After he puts in the message, he corks the bottle. This is clearly seen. As he rolls the bottle across the ground to Sponge Bob, the cork magically disappears. Where is it?
When Spongebob picks up the bottle, there is indeed a cork still in it. He's standing near the house, so it blends in with the door. Also, if you'll remember, Spongebob says "But Squidward, I don't have a bottle opener..."
When Squidward puts the cork into the bottle, he shoves it in all the way so that none of it sticks out of the bottle. This makes it hard to see. Also, the cork blends in with the door.