To remove a property value from a calendar, use the cscal utility modify command and specify the option with two double quotes ("") as the value for the option.
For example, to remove a description from jsmith:meetings:
cscal -d "" modify jsmith:meetings
To remove all categories from jsmith:meetings:
cscal -g "" modify jsmith:meetings
To remove “other owners” from jsmith:meetings:
cscal -y "" modify jsmith:meetings