She did a few more cleaning and tehn she decided to move onto the protection part. Namely using the Impervius spell. She decided to start at her desk. She tapped the polished surface with her wand, "Impervius" she said. Then she moved over to the windows that she had done. "Impervius" she said as she tapped each pane and frame. The corner niche was next to be placed under the Impervius charm. Sarah hoped it would work, it still puzzled her how so much dust and things got into such an unobtrusive corner of the room. She then started to go from desk to desk along her row and tapping all the polished ones and saying "Impervius". Now unless the professor purposely messed it up, they would not have to spend the next lesson cleaning it.

While she was at it, she took off her glasses, "Impervius" she said tapping the one lens and then repeating the procedue on the other. The whole class had worked together and it seemed now that it was basically all done. Even teh floor beneath Sarah was polished and clean. So she casted "Impervius" on it as well. Then she replaced her glasses back on her face.

Now that she had applied all the charms on the board at least once Sarah decided to do more. She went up to anotehr window and began to work on it using all the charms on it.