Rattling xbox noise

Use a vacuum cleaner attachment to try and suck the loose item back out?

If you have a active warranty I suggest you send it in.

You have several options:

If your console is still in warranty, simply start a warranty repair/replacement process under
https://devicesupport.microsoft.com.

If it's out of warranty, and you're unwilling to pay the repair fee, you might have luck trying to get the item to the lower right of the console's casing. Turn the console off, and hold the console so, that the lower right edge of the console is at the
bottom, and gently shake the console (flipping it around and upside down but in a way so that the right edge stays at the lowest position)

If you managed to get the piece to the lower right edge, simply set the console down and hope for the best.

Since this is an official Xbox forum, we can only advise against any self repair attempts.

Vacuum and compressed air can often help me if you’re not under warranty and unwilling to get it formally repaired. Taking it apart would also work, but i dont advise it because it voids any warranty you have

Which model?

Does it come for sure from the vent? Have you trued without a disc inside?

edit; ok in 2 years it COULD be actusy broken, but it seems very strange, also because the vent is very well protected