I finished another piece of terrain yesterday, started alongside the CD case tower. It, too, had been sitting around a couple of years, assembled but unpainted. I'm glad to finally finish it!
The littlest tower is a small spray can cap. The two middle-sized grey towers are old vitamin bottles, and the tallest is a Glenfiddich sample canister. The machinery is a broken piece of computer equipment from my office, with old sprue as pipes. The ladders and fences are hardware cloth. The grating is more sculptor form mesh.
The liquid is epoxy resin mixed with GW Scorpion Green paint-- what a fun color! This worked really well, but I had to find the right epoxy. The DevCon 5 minute I normally used turned brown the next day. Not really a problem, considering it's supposed to be some sort of toxic sludge, but I wanted to try and keep the fresh green color. I wound up using DevCon High Strength epoxy, which had a 30 minute work time and specified it dried clear. My test piece worked well, and then I mixed an entire tube in a plastic cup to mix and pour from. I was mostly done and went back to my cup for a little more, only to find the whole thing had become this hot, green, spongy epoxy biscuit in the cup! My guess is that, concentrated in the bottom of the cup, the regular heat from the epoxy curing actually accelerated it's own curing process. Anyway, I got it out of the room as quickly as possible!