What's the best way to remove side-caps from a Duncan Butterfly?

I want to remove the side-caps from my Butterflies so I can paint the inside of them. What’s the best way to go about doing this? The first thing I tried was to stick a knife in them and pry it off (like this kid) but that only resulted in a bunch of mangled side-caps (and some broken knives!) I then tried pulling the two halves apart and sticking a small paintbrush through the hole to pop out the sides–which worked great, until I realized that the axle is apparently Hercules-glued into the blank side of the Butterfly. I spent ten minutes trying to yank it out with pliers, but to no avail.

Does anyone know a way to get these side-caps out without damaging them? Any help would be greatly appreciated!

I cannot possibly say this is “the best” method…

I did the “poke through” like you described, and indeed it was a Herculean task to get the axle out of both halves. Man. That was some work. But I eventually got it!

I had a suspicion I’d want to get back at the halves because I might not like the silicone caulking I had dumped in, so I drilled a small hole directly opposite the other almost-hole that is an artifact of the moulding process. Yes, there’s a hole in my caps now. But I can screw in a small screw, grab that screw with pliers, and pry off the caps.

I’ve seen industrial-strength suction cups that are used for dents on cars. Maybe that would work.

I haven’t bought a butterfly in about 8 years, but the last one I bought I was able to remove the caps fairly easily with a knife. The axle came out of both sides relatively easily as well. But they may have changed the manufacturing process in the interim.

I don’t really want to drill holes in my yo-yos and the smallest car dent suction cup I could find was 12cm. The side-caps are about 4cm. Any other ideas?