how do I delete one of my Duplicate draft folders after converting pop to imap

I added thunderbird to my new computer while the old computer still had thunderbird up. I noticed that it tried to add my two account data after I created them, but the old accounts were for pop mail. After finding out that I needed to turn off getting mail (which was not working, but trying) I added the two accounts again as IMAP accounts. I discovered that I had to move my old folders to the new accounts (copy only seemed to work sometimes), but it was tricky and SLOW for large folders. The main thing I learned was that I had to click on the old folder in the pop account and move it to the TOP level of the new IMAP account. HOWEVER this was slow for many folders and did not work for the "built in" folders. I looks like files are first moved to the server, then back to the new account on the new machine. I think with all of my fumbling around trying to get the transfer to work, some of the files (it looked like they had html in them) got corrupted and would not transfer or even delete until I moved them to a temp folder in the same account, after which I could move the files which I highlighted, but I had to create the folder first. To keep things from being confusing I deleted the now empty folders in the pop account as I moved each one. As I said moving the files was slow, and until I realized this I might have tried to do moves too quickly. At any rate, when I was done I had several duplicate folders in the IMAP account when I was done. The empty ones I created all deleted ok, but there are still two copies of Draft folders in each of my accounts, one empty, one with my files. How do I remove the duplicate empty folder?