I had a mate who went a way for a couple years, came back and still had his harvest, but it had gone very very dry. He used to jar up roughly an OZ and put a slice of an orange peel in the jar and leave it for about a day. This did bring a little moisture back to the dry nugs, but it certainly didn't make it any better. The taste was still harsh, but it did smoke better. A paper towel seems like it'd accomplish the same thing, but I'd be a little more vigilant with keeping an eye on it. Would probably be best to dry and cure your stuff properly the first time around, but obviously this isn't as easily done as said, especially with large harvests.