Throw Away board.
Or should I paint over it and continue with it?
Another concept introduce by Nicholas Wilton in the course is the Throw Away Board. Have a board by the side of you as you paint. Use it to wipe your brushes, try out ideas, put your palette paper over it (upside-down) at the end of the day - anything you fancy. Throw it away at the end, or maybe it might just turn into it's own painting.