Unit Properties can store any applescript object by names. Remove Unit Property deletes a unit property with the passed name in the passed unit, or defaults to using thisUnit if no unit name is specified. If no value is present by that name an empty string is returned, not an applescript error.
Remove Unit Property (text, the key name of the property)
from unit (text, the name of the unit. Defaults to thisUnit)
remove unit property “last battery change” from unit “Kitchen Motion"