First, I'll go on record that this is not a recommendation, but just some thoughts.
Say you chase the prv thread, the bits are most likely to be quite small and trapped in the flutes of the tap. Also, they are aluminum, not steel. Now say you fashion small diameter tubing to the end of your vacuum-cleaner hose and vacuum out the hole. There will be strong suction indeed at the end of that tube. It would seem that the only bits that would avoid cleanout would be on the very small particle level. No, I would not like those drifting around in my engine, but it seems to me (this is where I will be slapped by people I respect, so I won't take offense) that these aluminum particles will not damage or plug the innards, but will soon sit atop the sump filter screen or be trapped in an external filter, if any. Finally, perhaps the tap is a fluteless thread chaser, ipso facto, no particles.
