HEET (not Iso-Heet) is 99% methanol, fwiw. [EDIT - pulled
the MSDS from Grainger although if you want to know what is in something, search for its MSDS and go to the source, rather than internet hearsay /ubbthreads/images/graemlins/smile.gif
Some washer fluids have higher amounts of methanol than others (but the highest seems to be in the 30-50% range), but most do not have much (~5-10% if that); a quick clue they don't is if it only states 32 F and up, where as the lower numbers (like -20 F) would have more %, but still has other things...seen various colors and I'm sure there are clear ones out there too (with the higher meth %) if that's a concern, but can't say that is 100% true..high meth % washer fluid is not common here, since we do not get cold weather, but it does exist of course. Be careful with washer fluid though, since many also have glycol (not good for W/M inj.)