Do It Yourself
Stuff that can be easily done with recycled materials
An Airlock for bottles or jars, useful when fermenting foods, making your own alcohol, fertilizer, composting or whenever you need to let air/gas out of a container but not let any air in.
An oven with two hot plates that I build in the kitchen at my current place. The hot plates and oven get heated by a single fire and the chimney goes out through a window. All materials recycled from the cave house where I now live, courtesy of previous messy squatters who packed the whole place with trash.
When moving in to a place that is trashed like our place, its very common to find that rats and mice have established large colonies. To get rid of them without killing them, some trap designs where created out of bottles, buckets and stuff like that. Some of it worked great, some of it didn't... my advice: get a cat, it took 2 days and one rat being eaten by Milo so that the only animals left in the whole place are humans and cats.
Living without electricity is not a problem at all, specially if you have access to used oil like we do (there are bins for recycling used cooking oil that we can check) Since we started using them and showing it to other squatters or communities, there is an Oil lamp revival movement in the island that is used not only when there´s no electricity but also to light places in a alternative and nicer looking way.
If there is something we recycle a lot, that is wheat flour and if there is something totally missing when dumpstering that is yeast. That is when Sourdough kicks in and teaches you that not only its free / cheap alternative to commercial yeast but also that it makes much better, taster, nutritious and long lasting bread, so good bye commercial yeast.