Electrolysis

To clarify, the blue ice cream looking stuff in the bottom of the bottle

>>7943307
a salt made out of the metal in the paperclips and chloride

>>7943312
Does it have a use? How can I learn more about what exactly it is?

>>7943312
Actually, is it copper chloride? Your reply gave me a new angle. The color is similar, and copper is cheap enough to use in paperclips.

>>7943314
I don't think you're going to get far with kitchen chemistry.

Something like this
https://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
will tell you what elements are present but is obviously inaccessible to you.

>>7943302
>>7943314
get a magnet and check if the paperclip is ferromagnetic, it probably won't
if not, it's copper chloride as >>7943319 said, if they were silvery shiny, it was electrolytically covered in chromium (chromium(III) salts are green as well, btw)
if it is magnetic, it can be be combination of green iron(II) and rusty brown iron(III) chlorides/hydroxides, but that shouldn't form the white precipitate
>>7943322
AAS is near useless for qualitative analysis, X-ray Fluorescence is better for that
but that doesn't matter, has hasn't access to either

>>7943388
I think the white precipitate is salt from some evaporated water. Some might have leaked, but I'm not sure how. The bottle was airtight because I was attempting to collect hydrogen and it was pressuring enough to slightly inflate a balloon.

>>7943388
Paperclips are magnetic, paperclip dispensers include a magnet to keep them corralled.

Google search on what kind of steel are paperclips made of gives a couple of sites that say they are galvanized steel wire ( zinc coated ).

You might also have copper from where the wires were attached maybe if that part was submerged.

>>7943322
Why not do it the classic way and perform simple, indirect qualitative analysis.
It's fun and colorful, exactly what OP wants.

He can even make his own H2S in his kitchen.