To answer Thomas H and Plaid Preacher: there is a valve or flapper at the bottom of the blowstick. Similar in form and function to the flapper valve in the bottom of the toilet tank. It keeps the flow of air one-way--into the bag. As far as cleaning out a sealed bag: you must condition it to seal leaks and condition the leather. Traditionally, mixtures of substances such as treacle, honey and whisky were used. Today, there are commercially made products available that use lanolins, antiseptics and parrafinic substances. Keeping the inside of the sealed bag clean means breaking down the pipes after playing to allow air circulation to try and dry out the innards of the bag. Or buy a bag with a zipper in it and use a moisture control system. These are simple to elaborate systems which fit inside the bag, attaching at the base of the blowstick's mounting stock. They use a variety of dessicants to dry the breath coming from your lungs into the bag. Humans are variable; some people are"dry blowers" and others "wet." Depends on the amount of moisture, saliva, etc., that you put into your bag when you inflate it. I tend to the dry side. Hope this helps. I am going to look into my bag tonight--not that there is anything growing in there!

JMB