Time Machine Backups in Trash

Hello, earlier today I tried to delete the backups.backupdb file from my external hard drive, as I no longer want to use that HD for backups. I just want a fresh, clean HD. The backups folder is considerably large (about 850 GB), and it's now in my trash folder. I tried to delete it (using Yosemite on a Mac Pro, by the way), it told me there were locked files. I said remove unlocked files, and then it began to tell me that it couldn't other files because they were "in use". At that point, I panicked and cancelled the trash empty. I tried to drag the folder back onto the external, but no luck there – it tried to duplicate it rather than move it. Even if I had gotten it back onto the external, I still don't exactly know how I should proceed from there. What should be my next course of action? Kinda nervous to do anything else as I'm afraid it'll damage data on my primary Macintosh HD, which is almost a full TB. Please no "You shouldn't have done that" comments – only helpful solutions.