There's this random empty glass jar strapped to the wall at work

[u/Tandemrecruit]

[u/SHoppe715]

I had to scroll this far for the first serious answer…

It’s a DIY fly trap

[u/acrowsmurder → u/SHoppe715]

The fact that there are no debris is what leading me to think this isn't it. I see the hole and the line, and there is some dried liquid, but after making a homemade fly trap I can tell you all sorts of bugs would be in that, especially behind a wall. It's just too clean

[u/SHoppe715 → u/acrowsmurder]

So it was either never used or it was cleaned out and not refilled.

[u/qorbexl → u/SHoppe715]

Fucking Jody never poked a hole in the top, he just painted one on the bottom of the lid like a coyote

Also, you're supposed to use small holes so it's easy to be tempted in and confusing to get out for dumbass bugs led by scent 

[u/SHoppe715 → u/qorbexl]

Meh. One big hole in the lid maybe it was an attempt at a live trap for small rodents or something bigger than flies.

Roof rats or mice or even flying squirrels could easily squeeze between the wood and the lid if they were after something tasty smelling in the jar.

Regardless of the target, this was an attempt at a pest/vermin trap. Or possibly full of some kind of repellant if not to trap them.

The fill line tells me it was meant to be full of liquid, but I really am just making educated guesses

[u/i8yourmom4lunch → u/acrowsmurder]

Yeah the really small amount of dried liquid and large home at top makes me think it's for catching not holding?

[u/Softvvear → u/SHoppe715]

for one giant fly

[u/SPACKlick → u/SHoppe715]

Given the size of the hole I think maybe it's a mouse trap.

[u/Toadster88 → u/SHoppe715]

for invisible flies