Thanks everybody for your thoughts. My tank is large enough to put chainrings in and immerse them completely so no need to faff with rotating them and cleaning parts at a time. Truth be told if I had to do that I'd figure it was quicker and easier to just scrub them with a stiff brush.

I don't have anything big enough to contain chainrings or cassettes for cleaning so the glass jar approach is out, although the bag idea sounds promising. I might just give that a try, it will also mean I can hopefully get away without needing a gallon or more of cleaning solution.

I guess tomorrow it's off to the bike shop, I don't have much cleaning solution left at the moment.