Originally Posted by unworthy1

I have seen some removable core stems that have 2 "flats" near the end so you can easily unscrew the cores and re-install. Either with a little plastic tool (wingnut dealio) I hardly ever see or a pair of small pliers, handled with care. I had a number of tubes with valve cores so loose the dust cap would take out the core with the cap! Pliers fix those.