Use the Compact FX option to remove intermediate renders resulting from soft effects. When you build a vertical edit and begin stacking many effects, intermediate rendered versions are created. This optimizes the workflow when entering soft effect editors and working on the timeline. You do not need to reprocess elements every time you make a change. However, intermediate renders take up additional space on the framestore and greatly increase the size of your archive. To avoid this, use the Compact FX option before archiving.
To have soft effects automatically compacted as you render, disable Fill with Intermediates in the Batch Setup menu.