Found a frame rattle. What to do?

[Goeddgr]

So I have been hearing this soft rattle for awhile. Always thought it was one of my kids cars in the rear door pocket. Not so much! Turned music up and walked around truck and it was LOUD! Crawled under truck and keyed in on a section of the subframe under the B Pillar. Sounds to me like a loose fastener. Likely dropped into sub frame during production (typical ford). Question is- what can I do about it? I can’t see any access to put a magnet in and retrieve it. Is there access under the floor carpet? It’s going to drive me crazy now!

 

[MadZeus Darknature]

Just my thought are use a magnet on the outside to move it around to get it out or drill a hole .

 

[Goeddgr]

Thought about drilling a hole, but also thought that might work better from inside than outside.

 

[Edwin]

So I have been hearing this soft rattle for awhile. Always thought it was one of my kids cars in the rear door pocket. Not so much! Turned music up and walked around truck and it was LOUD! Crawled under truck and keyed in on a section of the subframe under the B Pillar. Sounds to me like a loose fastener. Likely dropped into sub frame during production (typical ford). Question is- what can I do about it? I can’t see any access to put a magnet in and retrieve it. Is there access under the floor carpet? It’s going to drive me crazy now!

If there isn’t any access, maybe you can make an access hole by carefully cutting with a hole saw?
Or try poking around with a cheap endoscope camera off of amazon.