This article is classified "Partly real, partly fictional"
When you meet hostile aliens, you should probably want to eliminate them
before the whole Earth is covered. First you have to be (almost) sure it
is an alien you are going to deactivate (see "Alien Identification").
Here are some proven methods for exterminating aliens:
1) Bare fists are in most cases too weak a weapon, unless you are
a Cyborg. But in emergency situations they may be the only
useful way.
2) Sticks of wood, or some kind of staff, are quite good in close
combat. These objects can be found in a local forest.
3) The most effective close combat weapon is a club or baseball bat.
Softer aliens may perish while you smash it with a club. But if
the alien is armored, you better run.
4) The best weapon that a normal human can use is some kind of hand
gun. For example, a .44 Magnum is likely enough to stop most
lightly-armored humanlike aliens.
5) Against groups of aliens, hand grenades are quite good; they
may not kill them, but should at least injure them. Some of
them may only be frightened, but then you have got some time
to run away.
Eliminating is not always killing. You may capture and torture the alien,
so it may promise not to come Earth again (if it survived torturing).
If you feel too weak to eliminate an alien, try to find some group powerful
enough to do it for you (and Earth).
Maybe the best solution is to make peace with the aliens instead.