​Partner found this under the wardrobe in our new flat. Almost looks like a box within a box with slits in the top, measures about 20cm long and was filled with a clear liquid.

At first we thought the liquid was water but I splashed some on my lip by mistake and it tasted very strong- like a combination of salty seawater and bleach/cleaner. My hands were also dry and cracking after I touched it and it stung quite a lot.

If it helps the landlord was in the process of implementing a lot of pest control measures when we first moved so my first guess would be some kind of fly trapping device?