My gear has been locked away for about 2 months lately, found out over the last few days after taking it out I should have store my rifle muzzle down.
My safe's lined with a synthetic carpet stuff, and I have (or had...) a soft aftermarket pad on the rifle.
I was storing the rifle butt down, and obviously something between the carpet and the butt pad didn't agree with each other.
After the 2 months there the pad has gone to goo and half melted to the carpet
Lesson learned, muzzle down in future.