It demands a little practice.
Don't give up, and don't be afraid. They look smiley, but they're plastic, and have no nervous system ...
Really tough ones are the fat klickys. With these, only the rubber works out (it's possible to use the "Han's" hit, but it's much more difficult ...).
I usually do the hit, and it works perfectly with common klickys, but I follow the advice they gave me here: I change the leg for one specially set apart for this "opperation" ...
The hit must be quick and hard. It's like Karate or the like, when they break a plank, you know?: concentrate, over a hard surface (I do it on a hard wood stool, which is marked by some hits
); concentrate (klicky on the stool, you hold it really hard), and ..
HA!!!-crack!~ (suddenly and very quickly raise it up, and hit!). It's simple, but it's a kind of a martial art, it needs a little focus ...
(You might even try to scream: it might help, however it isn't necessary ...)
Practice, and you'll do it.
Gus