It's for balance. Leave them there, do not move them.
Yes mark daman is correct, these clips are essentially weights, balance weights to be exact. Through the manufacturing process of plastic mold injection, there will always be minimal I mean minimal variations in the material thickness Wich plays havoc on rotational mass ... These clips are precisely placed in order to insure the fan blades stay balanced. Precisely balanced blades not only insure minimal vibrations but longevity of bearings and fan motor as a whole.. hope this helps
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