Yes.

Made by the Elves?

No.

made by Dwarves?

No.

made by men?

Yes.

Made in the 3rd age?

No.

1st age?

No.

Made in Numenor?

is it a ship?

Made in Númenor? –No.
Ship? –No.

Something you'd take to battle? (eg: sword, shield, etc)

Second Age?

Something you'd take to battle? –No.
Second Age? -Yes.

was it used after the 2nd age? (ie in the 3rd age)

Made in Middle-earth west of the Anduin?

Yes to both.

Is it something you build? (eg a tower, a bridge, a wall)

Made/built in Eriador?

Is it the keys of Orthanc?

Is it something you build? –Yes.
Made/built in Eriador? –Yes.
Is it the keys of Orthanc? –No.

Tower of Amon Sul?

That's it!:)

Thread's yours, G55.

Thanks, Nerwen!
Ask away!

Is it a person?

Person - no

Place?

is it alive?

Person - no
Place - no
Is it alive - ??? it's not a living thing, if that's what you mean.

Object?

Person - no
Place - no
Is it alive - ??? it's not a living thing, if that's what you mean.
Object - no

Is it a law or ban?

Person - no
Place - no
Is it alive - ??? it's not a living thing, if that's what you mean.
Object - no
Law/ban - no

anyone???

Hm, got to admit I'm a bit clueless. If it's not a person, not a place, not a thing, and it's questionable if it's alive, what can it be?

Is it natural (i.e. not made by Elves, Dwarves, Men or any other incarnate being)?

Person - no
Place - no
Is it alive - no
Object - no
Law/ban - no
Natural - good question. No.

Sorry if the answer I gave to "alive or not" wasn't clear. It is not a living thing/creature, but metaphorically/sybolically speaking, you could call something of this sort of thing alive.
It is hard to give a clue about what it is without giving it away. It is somewhat a cross between "object" and "law/ban", but don't stick to the meanings of these specific words: this clue is on a broader plain.

Is it a Doom/Curse?