How do snakes get rid of waste?

they grow out of it, like a baby tooth is in the way of the molar. some thins got 2 go!
Periodically, as the snake grows, it will begin the process by secreting a fluid (mainly composed of vitamin A) between the outer layer, and the new skin forming underneath. This is what makes the skin appear dull, and causes the eyes to 'cloud over'. After a few days, the skin and eyes revert back to their original colouring. Two or three days later, the snake rubs its nose against something abrasive, breaking the skin, and simply crawls out of the old skin - turning it inside out in the process.

Depending on the age of the snake - the whole process can take as little as seven days or as much as two weeks.