Am a longarmer too and when I have a spool of thread that keeps shredding for no reason-after I have done a complete check/maintenance of machine....I will spritz the spool with some water.....just enough to dampen it and it will stop misbehaving. And, yes, putting in fridge overnight has been done, but sometimes just a small spritz and a ziplock bag while you have a cuppa will tame that thread.........