Do not let the battery drain completely. Put it on charge ( leave connected to your computer or other USB charger) once per month even if you don’t use the device.
After each use thoroughly rinse MNemo with fresh water, do not use any other chemical product. Ideally have MNemo clipped on a piece of line and move it forward and backward so that the wheel gets cleaned everywhere as well. Also move the pressure plate lever while washing.
If you have the feeling there still is sediment trapped in the base of the device or in the screen cover, you can unscrew both parts to clean them directly.