Some have published videos of the injection site where they've hung a magnet on it.

REV. 9:11 AMERICAN STANDARD-------10 And they have pointed tails like scorpions; and in their tails is their power to give men wounds for five months. 11 They have over them as king the angel of the great deep: his name in Hebrew is Abaddon, and in the Greek language "Apollyon". 12 The first Trouble is past: see, there are still two Troubles to come. 13 And at the sounding of the sixth angel a voice came to my ears from the horns of the gold altar which is before God, 14 Saying to the sixth angel who had the horn, Make free the four angels who are chained at the great river Euphrates. 15 And the four angels were made free, who were ready for the hour and day and month and year, that they might put to death a third part of men.