The eraser is a painted mask: brush over any region and it turns see-through, revealing the lanes beneath. No key colour and no uniform background are needed.
Open the eraser Select a full-frame clip and open Effects → Eraser. The full-screen editor shows the live composite with a paintable surface over it.
Paint the region out Brush over what should disappear. As you stroke, the lanes beneath show through immediately, with a light red marker over the erased area.
Tune the brush Size and softness control the stroke; a soft edge blends removals into the surrounding image. The Restore brush paints pixels back if you overshoot.
Save Save stores the erased area on the clip. The preview and the export both apply it, soft edges included, and it holds through transitions.
Refine later Reopen the eraser any time: your existing matte loads ready to extend, restore or clear.
Tips
The painted region is fixed, which suits logos, frames and locked-off backgrounds. It does not follow a moving subject.
For anything that moves, use the AI eraser instead: name the thing to remove and it is taken out across the shot with the background rebuilt behind it. That runs as a generation, so it costs tokens where the brush is free.
Put a clean background plate on the lane beneath to make painted removals invisible. The AI eraser fills the gap itself, so it needs no plate.
Combine with chroma key: key the uniform part, erase the stubborn corners.