I have a beef with most glue bottles. After only a couple of uses, the cap will stick shut. I finally came up with an easier answer to opening a sticky cap. The simple, shop-made grip shown in the photo at left makes opening the bottle a snap.
I made the grip from ½" plywood. I drilled a through hole for the cap and a counterbore to catch the lip of the cap (drawing at left). To install the grip, simply remove the cap, install the grip over the glue spout, and secure the cap back in place.