Q. My sponge looks like it has mold on it, is there a way to clean the sponge?

A. Make sure you are using distilled water. It is not normal for the sponge to create what sounds like mold. Make sure your work area is clean. Mold can be transferred very easily via:

1. airborne mold transfer in the room or case (often times if you see dirt settling on the sponge in a mirror shape as the slats on the case holder that is a sign that your guitar is exposed to potentially dirty air transferring to the sponge.)

2. dirty hands transferring it to the sponge.

There is a successful home remedy that you can use to remove the mold spots on the sponge, and it is also important to clean the Humitar Case to avoid any further issues.


  • Submerge product in 3% hydrogen peroxide for 10 minutes. Rinse thoroughly, wringing out multiple times to ensure all solution is removed. If stains or odor should still be evident, soak in a 5:1 solution (5 parts water for 1 part liquid bleach) for about 5 minutes. Rinse thoroughly, wringing out multiple times to ensure all solution is removed. Let dry before filling with distilled water. Note: Product color may alter slightly.

Humitar Case:

  • Submerge case in 3% hydrogen peroxide for 20 minutes. Pull out and scrub all surfaces with toothbrush style brush, rinse with water, wipe clean and let dry.


Q: My sponge is hard and will not saturate water, what do I do?

A: You will need to heat up your distilled water and let the sponge soak in the water warm. With cleans hands massage the warm water in the sponge to help saturate the sponge.


Q: Can I purchase replacement sponges?

A: Yes, Replacement HumiBar (MN301) are available through Sweetwater, Musicians Friend and many other online retailers and local stores. 


Q: What does "LL" & "HH" mean on the HumiReader?

A: The HumiReader reads a humidity range of 20% - 99% and temperature range of 32 F - 122 F / 0 C - 50 C, if your humidity or temperature are below those ranges the reader will readout "LL", if they are above those ranges the reader will read out "HH".


Q: How do I reset the Min/Max? 

A: You can reset your Min/Max anytime by holding the Min/Max button down for 3 seconds. 


Q: I need to replace the battery, what do I buy?

A: You will need a AG13 battery.


Q: Can you calibrate the HumiReader?

A: No, it is calibrated at the factory to function with a +/-3% accuracy.


Q: My screen on the HumiReader won’t turn on, what can I do to fix?

A: First, replace the battery with a new AG13 battery.  If the screen still does not turn on, ensure the negative side of the battery is facing down into the unit and the positive side is facing you.  If the screen still does not come on, sometimes the contact gets bent and the battery is no longer making contact to power the screen, push battery down and see if the screen illuminates.  If so, fold up a small piece of paper/foam and place on positive side of battery.  Slide the battery door shut, this will allow the battery to make proper contact and illuminate the screen.