Can't delete Time Machine backups.

Hi. I used Time Machine to backup my laptop (Mavericks OS X 10.9.3) onto an external hard drive. Time Machine created multiple backups over a period of time, and I wanted to delete some of the older ones to free up some space. However, I now have 5 different backups in the trash, and when I attempt to empty the trash (secure empty) the trash window pops up and counts over 200,000 items for deletion, but then disappears and deletes absolutely nothing. Now, the trash is always full when I connect the external drive. I tried to move the backups back onto the external, thinking maybe there were too many files for my Mac to handle, but the computer simply started copying the files instead of transferring them. I don't want to reformat the drive or anything like that because I don't just use it for backups and would lose a TON of other work (music, pics, etc.).

Does anyone know how to get the trash to delete these backups? It's not just that the backups won't delete, but I can't delete ANY other files from the external as long as those backups are in the trash. HELP!

p.s. Oh, and I did try holding the alt/option key while emptying the trash, but that didn't work at all.