When it comes to rusted screws, as already mentioned it is hard
to find good replacements that don't have the threads dulled by
the plating or rust protection.  But what is best -- to remove
the rust and use the screws only to have them rust again?  Or to
use new screws that don't have the holding power of the old ones.

I have chosen to knock off the rust and reuse them without rust
protection in some cases.  Contrary to what I expected, things rust
here in the desert climate.  Is there any way to effectively
re-coat the screws?

Bill Chapman - in dry La Quinta, Calif.,
62 degrees, bright sun and windy