[ACademic]

If there is enough gap under the cap to slide a wire zip tie, then try this. Join two zip ties together so that you form a large circle. Place one of the edges under the cap and use the circle (wear gloves) as an elongated pry bar by grabbing it firmly and pulling toward you. It should pop off. If that doesn't work, then build a second circle (using another two zip ties) and place them on opposite ends of the cap. Pull on them together and if doesn't come off then, well I'm out of ideas after that.