I've just read the same tip elsewhere, good call but use it sparingly.
Before reassembly you can verify the threads are all clean and undamaged by using a bolt with the same thread pitch (M10 oil drain bolt is the same I think)
Use the bolt's threads to force the soft metal of the bearing retainer threads back into good form, use a small angled file if needed. Clean and check the threads in your hub before new bearings go in.
Here's a screenshot again from SOHC4 member Evanphi's build thread. (I hope these guys don't mind being quoted)