Fragmentology

The first object looks to be a rusty petrol cover. The second is the wind blocker from a run-of-the-mill butane lighter you can find at any petrol station.

The top one is the little door for the gas cap off of a vehicle of some sort. The hinge, shows the axis of motion, the spring that is holds one default position, and the little dimple a place to insert one's finger to pull it open.

The clincher is the bubbly rust patten on the right side showing that that side was oriented down and then that this is off the right side of the car.

Very good, guys! Elegant interpretation, Ukko. Richard, what did you need to identify the shiny thing?

I know it's not a complete id, but are they lids of some sort? I am seeing some kind of hinge and a lip for lifting?

the shiny thing is a clip?

The inset flanges at the corners of the shiny thing are a common manufacturing convention for snapping a piece into an assembly. The orientation of the flanges gives away the direction of assembly. The lack of rolled edge along that side means it is made to form a contiguous surface with the sides of the larger object, and the rolled edge around the remainder indicates it is made for comfortable handling. The semicircular flanges along the top rolled edge appear made to meet in the middle, which gives away the diameter of the finished object. You know this much before recognizing it from having handled too many butane lighters.

The spring-loaded cover might be for fuel but could also be a service-access cover.

Oops, I forgot to notice, on the lighter-top, there is an inset notch marked with a double-arrow that has a + and - symbol at each end. Therefore likely it straddles some kind of flow control in the finished object.

Ah, children, you're making the old man proud! D.O.F., you must be an archaeologist, at least in spirit!

Why is the top thing painted burgundy? And what's the white splotch to the left on one side?

Don't touch that flux capacitor!

That's right, Mustafa. Touching your flux capacitor may make you go blind.

Seriously, Martin, what kind of archaeologist are you?! Clearly the top circular disc item is some sort of death mask. The "back" is actually the front, and it clearly has two eyes, a nose and a frowning mouth. The burgundy is obviously red ochre, and the white is probably some sort of zink, which indicates that this mask has had important religious significance. The question is, where's the skeleton that belongs with it? (Yes, I am poking fun at the establishment.)

CR McClain has a followup for you.

The bathythermograph looks like an alien probe.

Christina:

You've read Motel of the Mysteries, I take it?

I wasn't too sure what the top thing was, but I was right as far as it being some sort of car part. Didn't really notice the paint, though, so I didn't realize it was an outside part (thus the fact that it's painted). No idea on the white splotch -- maybe a spider web of some sort?

Check out what's on the other side of the white splotch, and consider what the surrounding surface is like. Ukko read those signs very well. What can the white stuff be?

The white substance appears to be a rust repair putty, like Bondo.

Exactly! The reason it's so white is that I took a sander to it a few months back while touching up rust spots on the car. Finally, my brother got me a used lid in better shape. He even managed to find the right colour.