Fill a bath with warm water and add a small bit of fairy liquid or similar.

Place the cell into the water

Gently hold the cell

Rock the cell from side to side. Ensure the cell is not scraping the bottom

Lift the cell up and let the water drain out.

Repeat for each side of the hexagon

Remove from the bath and leave to dry

Vent Axia tehnical support told me the cell can be a little damp but ensure all water is out the cell.