At the end of a game, we grab up the tiles in small groups & stack them. Then I put them in the box randomly. I have so many tiles that the placement in the box must be an efficient use of space so they are on an edge & in rows. To set up a new game, I take the tiles out & place them in stacks, usually over a dozen stacks without looking at the fronts. This is sufficiently random going into the new game.