Worth, you are spot on. We are taught in the MFP course to wash the jars and rings after the 24 hr point before storing. I don't leave the rings on due to the reason you mentioned...safety. If something goes wrong, the lid will pop off or loosen. If the ring is on, you might not notice. (also a good idea to check your jars on a regular basis...something I am lax about) Washing the rings removes any food residue that will make it more likely to rust. The jars, rings, and lids are not made with the same quality as they used to be.
