So I just got a free soap berry in the mail to try out. I've never heard of them before, but apparently, you boil the berry and then wash your hands with it, and it has some kind of natural lather. I'd like to try it, but I'm hesitant to use it to wash my hands, because if there's some kind of residue I don't want it getting in my tanks the next time I do a water change. It's supposed to be "natural" but there's plenty of natural stuff that can be toxic.
Has anyone else used one of these? Do we know if it's safe?