I use my old antifreeze to winterize water cooled ice cream machines, then when started in spring, it goes down the drain to the sewer plant (which is able to handle used coolant, according to them)). Beats wasting brand new!
Tractor tires are filled with fluid and air for weight to improve traction. Back in my younger days we filled them with a mixture of water and a salt (calcium chloride). Tractor wheels have 3 part valves: one mounted in the wheel, the next one out is larger and would fit on the nozzle from the fluid pump and the smallest one was at the tip for air. At least that was how it was back in the day. Probably something similar with anti-freeze.
Since this is literally comes from all makes and models, I wonder if it's gelling up because of that. Is it even possible to see the actual coolant well enough through those bottles to determine that?