Inking is the term used for applying the contours of the animated objects and characters on the recto of a cel. This can be done with a brush, a pen or a marker.
Clean up is a stage in the workflow of hand drawn animation. The clean-up animation follows the rough animation, which consists of loosely made sketches of the movement. When these sketches are approved by the animator or director, they are reproduced in the clear and clean lines that make the finished look of the animation.