When we first see Alfrid with the Master of Laketown, he is talking about the rebellious people. On his left shoulder is a big splat of yellow goo, probably from a thrown egg. In the previous scene, where he confronts Bard and tries to have the barrels of fish dumped in the water, he hasn't got the yellow goo on his shoulder yet. In the extras of the Extended edition it is revealed that there was a scene filmed where Alfrid was pelted with eggs by the townsfolk when he walked to the Master's house, but the scene was not included in either the theatrical or the extended version. The egg also explains his line: 'the mood of the people is turning ugly'.
In the beginning of the scene in the Master of Laketown's house, Alfrid tries to empty a chamberpot through the open window. During this, the window half closes, so much of the contents of the chamberpot splash on the inside of the window and windowsill. In the extras of the Extended edition it is told that this happened during the first take, and the scene was reshot many times. Nevertheless, the first take ended up in the final cut.