Then there s the fact that wood of the same species varies from one tree to another and even within the same log. Go play lots of guitars, trust your ears, and don t pay too much attention to the preferences of others. Before making the decision to humidify an instrument, it is important to make sure that the surrounding environment is indeed dry enough to make this step necessary. Look at it every day for a week. The point is that you can t do this by the seat of your pants.
Some people throw half potatoes into their cases to humidify their guitars.
Others make their own humidifiers out of sponges and plastic soap dishes with holes drilled into them. Commercial humidifiers range from tubular rubber and sponge inserts to plastic-enclosed porous clay tubes. The goal of all of these objects is to evaporate their stored water over a period of days. If you leave your guitars outside their cases, you will need to humidify the room or the whole house. Inside the case, any commercially available humidifier will do a good job.