Care for your MüB.
The most important thing to any fine instrument, up there with how well it's been built, is how well it's taken care of. It should be a fairly straightforward process. Instead, it's pretty clouded by misconceptions. Let's clear the air.
Cleaning your bass is the easy part: use a good product made for the instrument you own. Finished wood and unfinished wood require different products. With lacquered/coated wood what you are actually cleaning is the finish - nowadays mostly a chemical product. The purpose of cleaning this kind of surface is to wipe off sweat, dust, smudges, fingerprints, lipstick, beer spills, Hello Kitty stickers and such.
Unfinished wood, instead, needs to be nourished, as much as cleaned. A maple fretboard is usually lacquered, so the above process applies. Otherwise, chances are that the wood is fully exposed. Take the habit of waxing it or oiling it every time you change strings. regularly. If you are a J. Jameson worshiper, please set a date on your calendar. How often really depends on how humid or dry your environment is. Probably every two or three months is a good starting point.
Which leads us to the next and way more important topic: humidity.
Misconception #1, 2, 3, ... : "My country is very humid/very dry".
It doesn't really matter what the climate out there is. Your bass doesn't know whether he (or she) is in Scotland or the Death Valley. To it 'climate' is the environment in the room where it spends most of the time - a.k.a. Relative Humidity.
Without getting too technical, it is widely accepted that, wood is ready to be used in instrument building when its moisture content is between 6% and 9%. Throughout the building process moisture from glue is allowed to dissipate and wood is kept at ideal RH. Then the instrument travels to you and settles into your environment.
RH is greatly affected by us. When we turn on the heater in winter, we artificially change the humidity level. The colder out there, the more heat we pump indoor and in a matter of a few weeks the Relative Humidity in your room can drop dramatically. Wood must balance its humidity level to that of the environment it's in. So it will absorb or release moisture until a balance is reached. Both a very low (or high) RH level and the speed at which said level is reached can be a shock to the wood with potentially devastating effect.
Very high and low humidity are both not very good for wood. It seem though as if low humidity were topping the list of often recurring problems. Why? Maybe because we are more likely to affect our RH level the way described above than purposely turning our room into a rain forest. (But we'll talk about high humidity too).
When humidity quickly nosedives, fret ends sprout out, wood starts cracking, exposed fretboard flexes and twists trying to free itself from the glue as it shrinks. This will continue until the wood has found an equilibrium. In the process the neck might starts twisting under the concerted action of board and strings. You don't want any of that to happen.
To prevent damages to your instrument due to low humidity you need: 1. A humidifier. 2. A hygrometer. The latter tells you what the relative humidity level is (which is more valuable than what Weather Channel says about your area). The former makes sure the humidity in your room stays at the right level. Which should be about 45% give or take.
Humidifier and hydrometer. You need them. Go get them. Keeping the instrument away from the heater is also a very good idea.
Understanding RH makes helps us deal with high humidity as well. Anything above 60% is not good, especially if such a level is kept for months. Above 80% you are in danger zone. A hydrometer will tell you where your RH stands. High humidity makes the wood swell, bend, twist; glued areas can come loose. Nothing pretty there.
Keeping the bass inside its case with silica gel bags helps. Replace the humidifier with a de-humidifier. It's all about keeping your RH in the 40-50% range.
D'Addario sells a patented product that promises to keep humidity in your instrument case at optimal level, releasing or trapping humidity as it moves below or above the ideal 45% level. Check it out here.
Hopefully, reading this has clarified the true nature of humidity-related problems. At the very least we hope it has conveyed a sense of urgency. There's so much literature on the internet: read as much as you can, know your enemy and act.
Remember, once you take charge of your bass its destiny is in your hands.
Thank you for reading.