How should I cover these human drawings/paintings?

I have a sketchpad that I used to draw humans and other things in. I used pencil, charcoal, and pastel to practice. Some of the sketches are humans. I also have a medium sized canvas with a painting of a lady. Should I use a black marker to go over and cover the human sketches and then tear them apart and throw them in the bin? For the canvas painting, should I use white or black paint to paint over the lady and then paint on that if I want? (I cannot tear or break the canvas because of how thick it is). Is this the correct way of getting rid of and covering the human drawings?