Madhatter said:
clutch system is separate from brake system ... got to wonder what caused a loose line ....
Likely he is just working with the clutch side. Since both use brake fluid, minor communication gaps in some posts.
FWIW, I used to work in the hydraulics industry. I agree, water would have been better than motor oil, in an emergency. The basic need is for a non-compressable fluid. In some applications we used grape seed oil instead of standard hydraulic oil when environmental issues required a bio compatible fluid in case of leaks or contamination, (like wetlands and saws/cutting tools). I'd probably use any high quality cooking oil as a emergency alternative for brake fluid before using a petroleum engine oil. Preferably one that is only one ingredient, rather than a mix of ingredients. Olive oil over generic cooking oil, for example.
At this point, the clutch system is thankfully smaller and less complex than the brake system, so flush it well and fix what ever was the original sin, then time will tell.