disk image not deleting from trash in 11.0.1

I made a High Sierra bootable disk for my '11 iMac with my '15 MacBook Pro running Big Sur. After I made the USB stick, I deleted the install disk image and now when I try to empty the trash, I get a file in use error:

"The operation can't be completed because the item [filename.dmg] is in use."

When I try the "Delete Immediately" command, I get the error:

"The operation can’t be completed because some items had to be skipped. For each item, choose File > Get Info, make sure “Locked” is deselected, and then check the Sharing & Permissions section. When you are sure the items are unlocked and not designated as Read Only or No Access, try again."

I have tried everything I have looked up to do including some Terminal commands and starting in "Safe Mode" but nothing is working.

Any help would be appreciated.