There is a certain weight of water that each will absorb, then they are “full”
and you have to replace them or dry them out.  The small packs can’t absorb much
at all, but I suppose a whole load of small packs would do something.  IMHO they
also depend on their being enough moisture content in the air, and if there was
just a small amount of moisture but something for it to react to like sweat or
Muriatic acid, then they wouldn’t stop the rust.

Ed Minch