I have to disagree JM. I think the casual nature of knit ties does not lend itself to a tie clip, which, in my mind, is a formal accessory. Not to mention the tie clip has the tendency to squash the springy, crunchy knitted silk, which is far better to be left to pop from your shirt.
I think a kilt pin style tie clip is more appropriate for knit ties, but I won't deny it's a look that's not for everyone.Warning: Spoiler! (Click to show)