RE: Preserving Gorilla Glue?
I got the crusty formation around the cap when I stored mine upside down, too.
I live in the Midwest, which is known for its humidity, so I noticed a tip on a British forum which I am currently trying out. I used a small plastic "soft oleo sized" container with a drying compound you can buy at Wally World for damp closets and cellars. The compound comes in a 1/2 gallon carton as a refill for their closet dispenser unit. I poked (drilled) holes in the lid of the small container to allow air circulation, then put it into a larger (gallon ice cream sized) container. Next go in all the water-sensitive adhesives.
So far (three months) it works. Takes longer to read my tortured explanation of it that to do it. Good luck, Dzl