I think I posted this before... Being I have a (few) old skool kites, I lifted a tool similar to this from the kitchen

By holding the spar in your hand and inserting it in the groove against the fitting you can then push with your thumbs and the spreader will slide out easily...I find it works great to pop off the end caps of a REV that has collected sand in between the cap and spar...especially nice when your hands are a bit cold
the picture is from amazon, but if you Google oven rack push pull tool you'll find some, hey get 2 they work great in the kitchen also