How to stop SAP from automatically populating fields in SQ01

When I go to run a query in SQ01, some of my fields are automatically populated from SAP memory. I have to go through and clear them all manually. Even if I call up an existing variant, which has those fields as blank, the values in the fields still seem to "stick."

How do I tell SAP that I don't want fields automatically populated? I tried using parameters (such as MAT) and left the value blank, but that doesn't seem to work.