Remove Thunderbird email account

I need to delete a no longer needed email account, plus all email for that 
account from Thunderbird.

Thinking I knew what I was doing, (ha).. I went into account settings, 
highlighted the account, and using the little "Account Actions" down arrow, 
chose "REMOVE ACCOUNT"

It went away alright, but the mail is still there on my computer and in my 
profile under the "MAIL" directory.  For those who like details that's:  
Thunderbird > Profiles > Profilename > Mail, where the unwanted account has it's
own folder holding all mail ever sent or received.  There are also three other 
account folders I want to keep.

Is it OK to just delete that unwanted account folder without messing up my 
profile?

-- 
Barbara