I'm assuming that they gave you some big syringes. After EVERY use of the tube, suck up at tleast two full syringes of warm water and shoot it into the tube after you detach the bag to flush it out. It should always look clean and clear, with no build up in it when you are done eating. I also used these for putting my meds in my tube and then again flushing the tube afterwards. If you have some kind of buildup in the tube it could be a breeding ground for bacteria, and they may wish to change it if they are on the ball, and that is no big deal...5 minutes of time and no discomfort. The bags themselves I tossed very week and started with a new one, ditto the syringes.