Through hole desoldering. Got solder stuck in a stubborn hole and having trouble getting it out? One of the big sources of desoldering frustration can be if a through hole is connected directly to a heatsink or ground plane, because the heat will get conducted out to the plane and the joint will not get hot enough to clear the solder away. One good trick is to use a hot air gun to help heat the joint up a little hotter so you can remove the solder. Another trick is to put some bare solid copper Cat5 wire through the hole to clear things up better.
Finally, a good point to note. Solder wick can cause you trouble with desoldering because it can soak up some of the heat and subtract from the heat available to apply to the joint.
20200525/https://68kmla.org/forums/index.php?/topic/59764-trick-to-desolder-thru-holes/