Grab a machete and let loose.
(For that Out of Africe feeling)
Another good one is filling their mouths with Gunpowder and lightin it up, instant "puff the magic dragon"
Another is grabbing the foaming hair product with the "tube" nossel and bloating them.
The worst I've seam is litterally cutting their heart out and letting them go, they last about 30-45 secs then croak it.
Or fill a cardboard box with them and shooting into it with a sir/slug gun.
You could always "nail" them to a cross and leave them there...
Problem is you can never get rid of the buggers, they just keep on coming back
just a note to the viewers, that I'm aware how bad those things sound, they were done by a much younger me and I do not condone them anymore, it's just the alcohol talking lol