You will always have moisture in you cabinet, even with modifiers camels, golden rods etc., the issue with cardboard is the adsorbancy. nothing to do with water but the fact it strips the oil from the steel of your muzzle. If you have rifles and guns that are not regularly shot or oiled you will get rest in the last inch of the bore A good foam non absorbent pad will not wick the oil from your rifle. I ruined a barrel like this some 20 years ago using a canvas pad. When living in western QLD (really low humidity) we used to have to put a piece of flannel in the end of the bore to stop the hornets nesting (mud) in them. had to be real careful about this creating a rust situation long term.