I'm going to take markers away from children
Why are you taking the markers away?
I do not want to clean up after them any longer.
I can see why you'd be tempted to do this. Instead of taking them and depriving them of a creative outlet, maybe focus on teaching them how to use them properly and clean up after themselves.
I plan on taking their markers and throwing them into a river.
It just does not seem like the best plan to take away their drawing utensils. Drawing is a great way for children to express their creativity and imagination. I truly feel that cleaning up is the main thing that they need to learn here.