Hydrocarbon are hydrofobic, you know oil and water don't mix. Dot 3 and 4 brake fluid is hydroscopic and freely mixes with water. They are not the same.Why can't you mix it with oil? Brake fluid is also a hydrocarbon.
When I returned coolant and motor oil, the guy at the recyling facility took my jugs and dumped the coolant into the same tank as the oil.
Does this mean that the oil can't be recycled now because he contamined it with water?
When the oil is recycled, I believe they remove the water, and then fractionate the oil, because its expected to be contaminated.
All the car pars stores around here won't take oil mixed with coolant/water.
The main thing with used coolant is don't leave it sitting out. It's better to dump it on the ground or dump it down the drain than have an animal drink it.