Zero Harm can be done adding a Moisture Absorber to capture any sweating of the materials that are removed from being airborne.
No Harm in having these under Audio Devices as well, as Humidity within the Casing is detrimental to electronic circuits. Check Visible Screw Heads externally for rust corrosion developed and the effects of Humidity already has commenced.
Question is how is the Circuit after being exposed to conditions causing rust corrosion on the devices casing.
Casings are not Hermetically Sealed.

