To remove a property value from a calendar, use the cscal modify command and specify the value of the option with two double quotes ("").
The three examples that follow show how to remove different properties:
To remove a description from jsmith@sesta.com:meetings:
cscal -d "" modify jsmith@sesta.com:meetings
To remove all categories from the jsmith@sesta.com:meetings calendar:
cscal -g "" modify jsmith@sesta.com:meetings
To remove “other owners” from jsmith@sesta.com:meetings:
cscal -y "" modify jsmith@sesta.com:meetings