Hello guys. I bring you update. I partly succeeded in soldering for the first time in my life. Here is why i said partly:
As you can see from the video above, the zapper works but not as it supposed to. Prior i was able to feel shock and see sparks when touching zapper with hand, but now i can only feel voltage without usual static discharge. Did not try on insects by the way yet. Also when i touch with drill bit, i see some little sparks.
Here is a solder i have used:

Changing batteries does not make any difference.
Maybe i did not let flux cleanse dirty solder enough as i did not solder on flat surface but above it more like in the air? Anybody has any ideas what could be wrong?
By the way i read that solderer's tip should be cleaned with damp sponge but i have tried with scotch which i wanted to throw away anyway before. Scotch started gluing to solderer so i think it was a bad idea. Here is what i used exactly:

Was i wrong to use this and will damp sponge work better?
Thanks to all respondents beforehand!