And for anyone worried about screwing up their machines with a mixed (or non-OEM) flush solution, the first test I always run is a drop dispersion test. Fill a shotglass (or other suitable small container) with the flush in question and drip a single drop of ink into it. Let it sit for 1 hour or so and check it.
The ideal you want is a solution of lightly colored liquid with a minimum of settling. You can stir gently with a toothpick if you want to check. If you see little threads of color in the solution, then don't use it -- it will coagulate your ink and cause more problems.
Now, that doesn't cover chemical compatibility with the machine components -- but long story short, if you're using a solvent machine that's newer than the FJ-50 / Falcon Outdoor era, most of the plastics should be polypropylene or polyethylene and resistant to everything up to mild solvent. So the chemical suggestions in here are OK as far as the plastics go.