Clean the Board
From TEFL World Wiki
Here's a quick tip for TEFL teachers: Clean the Board when you've finished using it.
Why?
Well, there are two very good reasons for this. Firstly it's courteous to the next teacher who comes into the classroom to use the board. Secondly - and more importantly - it means that *if* you've made a mistake on the board (spelling or otherwise) then the next teacher who comes into the classroom won't see it!
Also remember to face the class when you are talking to them and not write on the board and talk at the same time!

