Here is a goal: How do I clean Out the Inside of the Bamboo?

Which way makes more sense to accomplish this goal?

(I). Using a half round file inserted into the hollow in the center of the bamboo and move it up and down while going around inside until the inside is smooth..
(II). Using a nail file inserted into the hollow in the center of the bamboo and move it up and down while going around inside until the inside is smooth..
(I).