As a rule, didgeridoos are pretty sturdy instruments.  Short of using one as a cricket bat, you would have to work pretty hard to do any serious damage.  None the less, here are a few didgeri-“do’s” and “don’ts”.

The mouth piece

Most didges generally have a bees-wax mouthpiece attached to the playing end. 
While this is not always necessary, depending on the initial width of the playing end, a mouthpiece does allows greater comfort to the player, as well as giving the player the ability to adjust the width of the mouthpiece to suite their own mouth shape. 

If your didge does not have a mouthpiece, or you would like to add to the existing one, make sure you only use pure beeswax.  This is obtainable in most craft shops, or from any bee-keeper.  Commercially prepared candle wax is generally unsuitable as it tends not have the malleability of beeswax due to hardening agents added in its manufacture.   This results in the mouthpiece usually cracking up and falling off if you try to adjust it.

As most beeswax comes in blocks, or small “tiles” you must initially mould the wax into a suitable shape before you can apply it to your didgeridoo.  To do this, place the wax in a bowl of hot water.  After the wax has softened for a few minutes, cut off a small portion, and roll it into a pencil-shaped length, and replace it in the water to keep it soft.  Repeat this several times, until you think you have enough lengths rolled out to build your mouthpiece (generally between four or five lengths will be sufficient).

Before you begin building up the mouthpiece, determine the balance of your didgeridoo.  This is important for several reasons.  Without determining where your didgeridoo’s centre of gravity is, you might end up having to grip the didge as you play in order to keep it from rolling around as well as having to lift it.  From experience, this added inconvenience can be extremely off-putting. To determine this, sit as though you were going to play the instrument, and rest the mouthpiece end of the didge loosely in your hand.  Let it roll in your hands until it reaches a static resting position.  Take note of where the top and bottom of the playing end is in this position. 

Once you have determined the didgeridoo’s centre of gravity, begin to build up the mouthpiece by firmly pressing one of the softened lengths of wax around the inside of the barrel.  If you find that the wax is becoming difficult to mould on, warm up a bit more water, and allow your wax lengths to soften again.  A quick blast with a hair dryer will also do the job nicely.  Gradually, mould the wax in successive layers, until you have developed a mouthpiece which feels comfortable to you.  This shape is obviously entirely up to the player, but I generally try to mould it into an oval shape similar to an egg sitting on a flat surface.

There is no need to replace the wax on a regular basis, but, depending on how frequently you play, good hygiene would suggest the occasional replacement.
 
 

Cleaning your didgeridoo

As you play, you will no doubt be aware that healthy quantities of spit (didgeri-drool) will pass through the instrument.  After a while, bacteria will begin to build up and fester inside the didge, particularly around the mouthpiece, and, if left long enough, mould will begin to grow.  This will inevitably weaken the inside of the didge, as well as producing an unpleasant fungal odour.  In an effort to avoid this, drink lots of water in between your playing bursts.  Aside from the health benefits derived from increased water intake, your saliva will be considerably diluted by the water.

Along the same lines, do not eat any food immediately before you play.  When you eat, your body produces enzyme laden-saliva as part of the early digestion process, and this, along with bits of food will be blown down the inside of the instrument as you play.  Also, try to avoid playing immediately after having consumed any fluid other than water; the result is the same.  Sugary drinks and alcohol are particularly bad.  As mentioned earlier, the build up of saliva in your didge, particularly if it contains food particles, will eventually damage your instrument, if not making it a down right health-hazard!

Occasionally, giving your didge a good rinse out will discourage any unpleasant build up inside your instrument.  To wash your didge out, add a table-spoon of water soluble tea tree oil (a natural anti-bacterial agent) to two cups of water.  Pour the solution into the bell end of the didge whilst blocking the mouthpiece end of your didge with your hand.  You might need a friend to give you a hand with this.  Give it a few good shakes to loosen up any built up material inside, and repeat the process.  After, allow your didge to drain and dry in an upright position.  You can also give your mouthpiece a good cleaning by occasionally applying some neat tea-tree oil to its surface and around the inside. 

NB  Tea Tree is a strong anti-bacterial agent, and it can be irritating to your skin.  Do not play your didge immediately after cleaning the mouthpiece.  If any signs of irritation develop, seek an alternative agent such as rubbing alcohol.
 

Looking After the Wood

Over the course of my career with didgeridoos, I have heard many stories of the necessity of periodically immersing the instrument in a tub of water to keep the wood moist.  If your instrument is completely un-finished, i.e. raw wood, this is probably sound advice as the moisture re-creates conditions in the timber whilst it was still growing.  The majority of didges, however, tend to have some sort of finish on them to protect the wood.  When you buy your didge, always try to ascertain what type of finish your instrument has been treated with so you can pursue the appropriate maintenance programme. 

Completely unfinished didges:

Although immersing it in water occasionally will probably keep the didge in good shape, I would recommend applying at least three of four coats of linseed oil to the exterior initially, then re-applying a coat every month or so.  This will protect the exterior from absorbing any water, while simultaneously keeping the timber from drying up completely.  I would also occasionally run a few coats of oil down the inside of the didge to keep the timber evenly protected.  To do this, place one end of the didge in a bucket, and pour the oil down the inside of the barrel, while slowly rotating the didge to ensure even coverage.  Repeat this two or three times to make ensure that all of the interior surface has had a chance to absorb the oil.

Water Based Finishes:

If your didge has a water-based finish, do not expose it to any type of moisture, as it will slowly degrade the finish.  Although this makes cleaning the didge a bit fussy (see above), if you take care not to expose it unnecessarily to moisture, your didge’s finish should stay intact for years.

Oil based finishes:

These finishes are my preference.  They simultaneously keep the wood underneath moist, as well as providing a hard, protective exterior surface which will protect the didge from water damage, and, to a point, any knocks. 

If you want to apply this type of finish, remove the mouthpiece, and carefully sand or scrape away any of the old finish until you get down to raw wood.  Sand the surface thoroughly, and then apply the varnish with a brush in a cool, dust free area.  Two coats even will usually provide a sufficiently durable finish, and make sure to sand in between coats. 

If you really want to protect your instrument, you can also pour the varnish down the inside of the didge. In my experience, this process brightens up the sound of the instrument considerably as the sound waves you project into the didge as you play will be bouncing off of a highly reflective surface. NB:  Only do this if you are using an oil based finish.  If you use a water based finish, your saliva will eventually degrade the finish inside. 

To varnish the inside of your didgeridoo, remove the mouthpiece, and place one end in a bucket, and pour the varnish down the inside of the barrel, while slowly rotating the didge to ensure even coverage.  Allow most of the varnish to drain out of the bottom, and then repeat the process using the excess varnish collected in the bucket.  Repeat this two or three times to make sure all of the interior surface has had a chance to absorb the varnish, and allow to dry for at least twenty four hours in an upright position.  When you are sure that the finish has completely dried, (check the manufacturer’s specifications to be sure), re apply your mouth piece following the previously outlined steps.

Like any wooden product, didges will expand and contract depending on their environment.  To a certain degree, they will be able to withstand these natural changes without any signs of stress.  However, do not leave your didge in a hot, dry, sunny spot for any prolonged period, as it will literally dry up and crack, regardless of its finish.  When your are not playing, try to leave your didge in a shady spot in an upright position.  This will allow your didge to contract at a natural rate as it cools down again, and will also allows any moisture which will have accumulated inside during the playing sessions to drain out again.  Although not necessary, a didge bag made from any sturdy material will protect the instruments from any knocks, and will keep any painted decoration from fading prematurely.