Open the Shorts List Page or the results view for your project.
Find the clip you want to remove.
Click the trash icon on the clip, or open its menu and select Delete.
Confirm the deletion.
The clip disappears from your list right away.
No. Ssemble deducts a credit when a clip generates, not while you keep it. Deleting a clip afterward removes it from your project but does not refund the credit, because the generation already ran.
See How Credits Work for how credits are charged and when they expire.
Refresh the page and try again. If the clip still won't delete, contact support with a link to the project so the team can look into it.