I had a Ruger #3 in .22 Hornet. In-between every-other-week uses I kept it in a soft case in my gun room in the basement. I poened the case one time and noticed spots of rust on the receiver. The damage was not much, but was a wake-up call. I started using SS-2, which is similar to WD-40 on the guns after that. Sure enough, I left in the case again when I was in a hurry. After an extended time I noticed that it was in the case and opened it expecting the worse. When I took the gun out, it had water droplets on the receiver, but no rust! The SS-2 protected the finish. I threw that case away.