Just how hard is it to kill a Troll?

alright here are my ideas...

Mountain (cave) trolls as far as i know don't turn to stone, only the forest trolls do
(but i'm not sure on that one)

And am i the only one who thought the trolls in the movies were too small?
maybe i just have a big imagination.

Also i got the impression that forest trolls were as wide around the waiste as tree trunks

But then again, i have only read the hobbit, LOTR and half of sil

[Gothmog]

My faith in the power of Hurin makes me believe that he was able to kill, if not 70 so at least plenty of trolls. I know I'm repeating others words but remember: they had orders to get him alive! And: he was the greatest warrior of men ever lived!

And can somebody please help me out: when did Ecthelion kill 100 trolls? (I'm too lazy to go trough the books right now and I can't remember that). At the fall of Gondolin??

By the way, has anyone seen the old cartoon movie? The fight in Moria in that one is more as I've imagined it when reading the books...

[Eomer of the Rohirrim]

Ecthelion is rumoured to have killed 100 Trolls in one go. I don't have an exact source for this claim. I only heard it on another thread. Perhaps this tale is told in HoME or maybe it is not true.

[Olorin_TLA]

Just like to point out, there are no such things as forest trolls in Middle-earth. The different names for trolls seem just to refer to where they live, and slight possible physicall differences (ie, snow trolls are white) - basically like you get snow leopards, normal leopards, black ones, etc.
The only truely different-from-Hobbit/Moria-trolls were the Olog-hai, who have no problems with sunlight as long as the will of Sauron is on them.

I think that in a face to face combat it is pretty hard to kill troll unless you are very quick, beacuse they are hard as a rock so not anykind of weapon will hurt them.....I think