Problem: Unusued Glue, No Cap
You have unused glue, and no cap.
Solution: Use a Wire Nut
A wire nut has a tiny metal spring that’s designed to create a secure mechanical connection between two or more wires, without requiring welding or soldering. Usually, they are used in electrical applications to create a “splice” – a connection between a primary source and one or more secondary connections that end up wired in parallel.
Wire nuts come in various sizes, but the “Yellow” and “Red” wire nuts typically fit larger tubes, while the “Orange” and “Blue” wire nuts usually fit smaller glue tubes. You can get a variety pack at your local hardware retailer for a couple of dollars.
When used on a tube of glue, the metal spiral forms a near-air-tight seal.
If you spent $5 on a tube of glue, why not protect that investment with a 30 cent wire nut??
When this happens:
On larger tubes, the red or yellow might fit. Twist until tight:
Now, your glue is safe and sound, and won’t dry out.