Dear Shai,
Yes, the NTM88 is washable, and different methods are possible regarding what to do with the hole in the package.
- It is possible to simply keep the hole open and dry out the board after cleaning. The sensor should not be damaged through the washing process as long as the diaphragm is not touched with any kind of brush. /!\ The cleaning material, if not water, must not have a negative effect on the sensor (especially the gel).
- Or, Kapton tape can be used to protect the hole during the washing process. The Kapton stickers are pick & placed from a reel and put on the sensor lid before soldering and cleaning and then removed. Removing the stickers is not so easy, so it may be a manual process.
- Another option would be to build some sort of a cradle/cover with an o-ring to snap fit over the sensor lid to protect the sensor during the washing process. The cradle could be re-used multiple time. This could be also some sort of a rubber boot protection over the sensor.
BR, Tomas