Care and Maintenance of a Tobacco Pipe
There are many different kinds of pipes used for smoking, but one thing they all have in common is that maintenance and cleaning is absolutely required in order to provide the most pleasurable experience. Proper care of a pipe extends the life, increases the enjoyment, and protects the value inherent in such an investment.
Regular Use
A pipe should only be smoked when it is dry and cool. This helps prevent damage to the joint between bowl and stem, as well as damage to the bowl itself. Excessive smoking of a pipe can lead to burnout in the bowl, which happens when the wood inside the bowl becomes hot enough to actually start charring. Also, a buildup of moisture inside the pipe can lead to nasty tar formation inside the stem. Believe me, that's not pleasant.
During smoking, be careful with the mouthpiece. Don't grip it between your teeth, as eventually you will wear through the tip or deform it to the point to where it is no longer useable. Don't set a lit pipe down on its side, because, a: you don't want to start a fire, and b: this will cause uneven burning inside the bowl, if it even stays lit. To light a pipe, use a wooden match. It burns cooler than butane torches and will cause less damage to the bowl of the pipe. Whatever you use, try not to place any part of the lighter directly on the bowl of the pipe.
When emptying a smoked pipe, a cork ashtray is ideal. Knock the bowl gently on the cork until the dottle falls out of the pipe. A pipe tool can be used to remove the rest of the ash, but be careful not to scrape into the walls of the bowl when using a pipe tool. Whatever you do, never knock a pipe on a hard surface. This can destroy a clay or meerschaum pipe, and even a briar will suffer damage if this is done too often. If you are outdoors or no ashtray is handy, knock the pipe into the palm of your hand (make sure it's out first) and then dispose of the ash somewhere.
Cleaning should only be done when the pipe is cool. The stem and bowl should only be separated after a long cooling period, or the fit will loosen and the joint will no longer be airtight. This joint can loosen to the point where the bowl will no longer stay attached to the stem and the pipe may fall apart while smoking. You can also break the stem of the pipe, just ask Wiccanpiper. To clean your pipe, run a pipe cleaner through the stem by itself. Use another pipe cleaner to clean the bore of the bowl, where the stem attaches. Clear the inside of the bowl of all debris, but be careful not to damage the cake inside.
When not smoking your pipe, store it somewhere cool and dry. A humidor is not recommended for most pipes. Place it on a rack with the stem upwards and the bowl down. Store your tobacco in an airtight container. The tobacco can be a little bit moist, it'll be a better smoke that way as dried out tobacco is harsher and hotter.
Most pipes will need to be reamed eventually. This process removes the excess cake from inside the bowl, increasing the capacity of the bowl back to normal and improving the draw as well. Ideally, the cake should be about the thickness of a dime uniformly around the bowl. A pipe reamer is necessary to do this evenly. Most tobacconists will be able to ream your pipe.
If there is a cork between stem and bowl, it should be checked often for fit and condition. If it is too loose, it should be replaced with one with a better fit. If too tight, you can carefully shave it with a razor blade for a better fit. The cork should fit entirely inside the bowl to ensure the best fit. If it is necessary to replace the cork, be very careful. Remember, any glue used to hold a new cork will be exposed to high temperatures and also may end up entering your system. The idea is to poison your body with pleasing natural substances, not dangerous chemicals.
The key to keeping a pipe in good condition is controlling the environment inside the pipe. Excessive moisture and heat will quickly damage any pipe, no matter what material it is made of. Every effort must be made to keep the inside of a pipe dry. Never wash the inside of a pipe with water, make sure a pipe is completely dry between smokings, and last, but not least, don't smoke in the rain. If you take care of your pipe, it will take care of you. A good friend once told me that a pipe is like a wife. Treat it with love, tenderness, and care, and, after 20 years, it will run off with some younger fellow and take all of your money.
References:
Old guys who smoke too much
Wiccanpiper
Personal experience