OK, I have been told that an elliptical clip is the result of a planchet error.
Think of a football shape when you think of an elliptical clip.
I understand that when blank planchets are punched from the sheets of coin metal and the process is stopped and then restarted, the alignment of the row of planchets might be punched to produce a football shaped planchet.
Think of a cookie cutter on the rolled out dough. If you have a round cookie cutter, you can cut the cookie two times but not right on the second time and the result would be an elliptical shape.
Then the planchet gets past the watchful eyes of the wide awake operator and onto the dies with the design and then it gets past there without being caught and into the big mint bags it goes.
As my sig says tho ....