I'm gradually emptying out the innards of a 1975 Kaltenbach cold saw. This is the kind of saw that has the blade inside (below) and the entire base acts as a sump for cutting fluid. I siphoned out about 4 gallons of the old stuff today. It's not quite as thick as a good chocolate shake, but it's very thick stuff. Not thick enough to form strings when it drips, but still, thick. It looks like some kind of emulsion. My guess is it's an aqueous cutting solution which has been sitting so long in a dry climate that all the bacteria have grown, reproduced, and died, and all the water has evaporated, or nearly all. But it might be cutting fluid. At any rate, it's funky and I'm not going to reuse it.
What can one do with stuff like this? How can I determine if it's oil or not?
I also got another gallon or two of heavy steel-chip-rich sludge. I'm also curious what the environmentally responsible thing to do with this sludge is.