rodemic NT-USB Mode D'emploi page 23

Safety & maintenance
23
After use the NT-USB should be removed from its tripod mount,
wiped with a dry, soft cloth and placed in the supplied protective
pouch.
Be sure to place the moisture-absorbent crystals (supplied) at the
head of the microphone, so as to absorb any moisture present.
Eventually this pack of crystals will need to be dried. This is
indicated by the crystals turning pink in colour. They can easily be
re-used by placing them in an oven at 100 - 150 degrees celsius
for approximately ten minutes. The crystals will operate effectively
again once they have turned blue.