I need to clear all fields for a document with the click of a button. This works fine when the field is a simple text field, I can use 'Set Field' to set it to a variable ('blankvariable') which is simply left blank. However when I try to insert this variable into a lookup list field, it does not work (I presume because there is no blank item in the lookup list).

Is there a way to get around this? I'd just like to strip out all properties other than filename