with that of the factory foil.
I am with you on this Cleandan, it seems like advice that was given back when tin cans with screw lids had not much seal or perhaps even in reference to open bottles without a cap.
I just used several old bottles I was too cheap to throw away, to flush thru the system on a truck I bought that apparent was contaminated with water and rust. After much flushing and observing the stream gradually turn from soupy to clear, it is apparent that clean brake fluid sitting in a can with a closed plastic cap is a LOT better stuff than most of what is in our cars.
How many folks flush their brake fluid every 5 years?