You may keep the instrument on a peg or inside the case. In both cases keep the instrument always in vertical position. This will help to keep the body in shape. Furthermore, remaining spill-water can run down the bore. In case, that there are small children or peds in the household, keep it out of reach.
2. Ensemble the instrument:
Take the bell and press in onto the lower joint. If your instrument has a resonance key mounted on the bell, watch out not to bend the connection. Hold the lower joint where the hand-rest and ring-key is. Avoid pressing the right-hand C/F lever. This is one of the most common reasons, why the C/F key gets out of adjustment. See also Adjusting the right hand C/F key
3. Next, take the top-joint, hold it tightly where the ring-keys are, and press the barrel onto the top-joint. Stay away from the two top side trill-keys. When you have an instrument with cork-pads, this would squeeze and break the cork-pads, which would result in a leaking top-joint. Even if you don't have an instrument with cork-pads, it's a good habit to get acquainted to. You might get cork-pads at one point or try instruments which have them and could cause unnecessary problems.
4. Press the topjoint with the barrel mounted onto the lower-joint. Keep an eye on the bridge-key to make sure not to bend it. This is in particularly important for bass-clarinets, basset-horns and alto-clarinets, where you have several connecting keys.
Swab the instrument:
Use only micro-fiber or silk pull through swabs. In case you can get hold of some large Goose feathers that would be even better. The swab has to go through easily. Avoid bottle brush type swabs or swabs which press against the inside of the bore. You only won't to remove excessive amount of water. the instrument does not need to be, nor should it be super dry.
Always pull the swab from the top to the button. The narrowest spot in the clarinet is where the register tube sticks into the bore. If a pull through swab gets stuck into the bore, you will always be able to pull it out if you started at the top. Dont pull the swab through the mouthpiece. It would wear out the tip too quickly.
Dry all sockets and tenons, even if you keep the instrument standing on a peg.
Wipe of the keys:
After you finished playing the instrument, wipe of the remaining finger sweat from the keys with a clean technical or microfiber cloth. This will help to keep the silver longer nice and shiny. Don't use a silvercloth to take of the brownish or black patina. Silver cloth are like sandpaper and remove the silver-oxide. A proper silver-cleaning is better done chemically with the next maintenance.
Screw and rods:
You might see sometimes, that a screw or rod is loose. If it is a rod, they go through the post and the key to the opposite post, dont hesitate to tighten it again.
If it is a Pivot screw, these are the ones which just go through the post and hold the key on one side, you might have to be more careful. Depending on the humidity, you might not be able to tighten the screw all the way. The key would get stuck. If that happens, just loosen it so much that the key can freely operate but without wobbeling.
We use a biological cork-grease called dear-grease. Ones applied, you usually dont need to do it anymore or if so, only very rarely. You want a firm tight grip and airtight connection. br>
Iy you use a Vaseline based grease, they usually come in form of a cork-pen, the grease needs to be removed from time to time. You can just use 70% alcohol or a paper-towel. If the joints are so loose that they could fall apart, get them renewed or wrap a layer of tape or paper around the cork before you push the joints together.
Check for leaks:
Regularly check for leaks or get it checked. A quick self-check is done on the top-joint by closing all open tone-holes with one hand (finger the C/G)and close the bore on one side with your thump. Then try to create a vacuum by sucking on the open end of the bore. Do it without pressing on the rings or any keys. Just lay your fingers lightly onto the tone-holes. It should be as tight as a bottle and keep the vacuum.
Do the same with the lower joint. This might need some practice and experience to be absolutely certain. If in doubt ask a repair specialist you trust.
Depending on the type of pads you have, get your instrument checked by an expert. Leaks start slowly and you get used to them. Its like driving a car, which has holes in the gaspipe. You dont notice it yourselfe while playing. You only notice it that your milage is down. Fishskinpads and Valentino pads should be checked ones a year. Leather pads after 2 years. Cork, impregnated leather pads and silentpads after 3-5 years. These pads last much longer but the tonehole might have developed small faults which might need to be taken care of.