Clear family type parameter value

Hello. I know, that Revit Api allows me to create custom parameters in .rfa files and set their values. For example:

foreach (var type in neededFamTypes)
{
    familyManager.CurrentType = type;
    familyManager.Set(myStringParameter, "myValue");             
}

Of course if I call type.HasValue(myStringParameter)  it will return true. But how can I delete paramter from type (not from whole family)? Something like  familyManager.Unset(myStringParameter) , and type.HasValue(myStringParameter) should return false then?