Gorilla Glue is ideal for repairing household items or making small crafts; it will bond to anything. It's available in small and large sizes of Super Glue and Wood Glue. The only downside to Gorilla Glue is that it can harden after about a year of usage or if it has been exposed to moisture. You can make it flexible and usable again with a variety of fixes, but only if a partial amount of glue remains, not a full bottle.
Step 1 Break the seal
If the surface of the glue has hardened to form a thin seal, break up the layer with a screwdriver. That should get the trapped, usable glue flowing again.
Step 2 Heat With water
Turn on the hot water tap to an uncomfortably high temperature to the touch. Pour the freshly heated water into a wide container and place the entire Gorilla Glue bottle into that water. The water line should be at a level high enough to come up to the level of glue that needs to be softened.
If a hot water tap is not available, heat a pot of water on the stovetop. Bring the water to a boil, but do not fully submerge the bottle in boiling water. Allow the water to cool at least 45 seconds before placing the glue bottle in it.
Give the bottle some time to sit. If it has not softened in the first heating, be patient and give it a few more tries.
Step 3 Prevention
The best way to give Gorilla Glue a long shelf life is to properly store it and seal it. Use a standard zip-lock bag to hold the glue in a shelf. For added protection put in a small package of silica-gel to trap and retain moisture that might compromise your bottle of glue. To get an even more effective protection use a vacuum sealer to completely melt the plastic with heat. This should make it impossible for any outside water to enter.