The way I clear cookies in FireFox is simply to remove them all in FireFox cookies window. After doing that, the problem is solved until...
I click the "Dansk" (Danish) item. I can then no longer get "English back" no matter if I type-in domain address or click the "English" button. I always get redirected to misvblog.com/da/
(Just tested/verified it again. But problem is only in FireFox, not Opera, IE, Safari, Chrome)