Selfsufficientish.com

Anyone got any clever ideas for empty 5 litre plastic water bottles? I have one as a storage point for my chargers and wires, and thought of either plant pots or plates. I have 2 spare at the moment, with another four in the future. Really don't want to throw them out (recycling not available for plastic where I am) if I can reuse them instead.

Self-watering plant pots.
Storage for homemade laundry liquid.
Frozen space fillers in the freezer - for those that have one.
Storage for old cooking oil, to take to the tip.

I use several (filled with water) in the garden for weighing down stuff that might otherwise fly off in the wind... Lightweight greenhouses etc.

bird feeders? Works well with smaller sized bottles and the design does not discourage squirrels...

https://inhabitat.com/how-to-make-a-bir ... materials/

I make a habit of looking for these containers that have been previously used for foodstuffs . If nothing else a food grade 5litre plastic container is worth at least a pound or more , check on eBay . Then what do I do with them? Well , perhaps a little boringly I fill them with water "just in case". By this I mean I like to keep a fair few containers of water ready to drink just in case there is distruption to the mains. Never actually needed it but it gives me a sense of security.
Containers that have held other stuff such as detergent , oil or glue are more problematic . I've used them for old oil and such but especially with those that have held glue there are nearly always residues that make it awkward to reuse for anything other than waste.

Fermenters?

The thing about plastic containers as fermenters (and I make my own wines, meads, ciders, and beers) is that alcohol is not water and the alcohol and acidity of wines (pH can be as low as 2.50 -3.00) and beers can leach chemicals from the plastic and some of those chemicals are known health risks. PET plastic won't leach but not all water containers are made of PET (at least not here in the USA). Ironically, I use 1 gallon (5 L) plastic containers for fetching water from a state sealed spring in Upstate NY, close to our home, for my mead making, but I use glass carboys for fermenting.

OK, how about cloches?