This book is also called (I'm Not a Cleaner). Traveling to a world where his destiny is awakened, something went wrong during the awakening ceremony for Li Jiuri - the light that was supposed to lower his destiny flashed away, and he was judged to have "collapsed his destiny" and almost became a "blank" with no ability.
His first item was a D-level [Public Toilet]. But it was this inconspicuous toilet that made him discover the secrets of public toilets: cleanliness, deodorization, and silence. With one life stone, business was surprisingly good. Every time the life stone is collected, it will be swallowed by the mysterious white card in the body, and the lines and light spots on the card will change quietly.
