Can't delete Time Machine Backups from Trash
I manually deleted a bunch of Time Machine backups from a Seagate USB drive (using Finder). The backups are in my trash, but I can't delete them. I tried the Option Delete and Shift-Option Delete, but I get the same results. The trash emptying process gets stuck after a VERY long time and says it can't delete certain files. If I disconnect the USB drive the deleted files disappear, but they reappear as soon as I connect it again.
Any ideas on how to delete what the delete dialog box says are about 4MM files! I'm running 10.12.6
iMac (21.5-inch Mid 2010), OS X Yosemite (10.10.1), null