We put them 'away' on a shelf in her kitchen, and she pulls them out almost everyday to play. Sometimes she gets a little excited, and beans go flying, which means the end of "Beans" for the day, but usually she's really good at keeping them in, or putting them back into, the bowl. This is still a 'supervised' activity, as she occasionally likes to put them in her mouth, and like I said, occasionally 'splashes' them across the room... But I see a lot of new discoveries going on with it, so I think its worth the occasional stepping on a dried bean, and the potential for a 'bean catastrophe' if she gets the lid off when I'm not nearby!
We're going to try out some different textures soon. We were given a 'water table' that will come out on the porch once the weather gets a little nicer. And we'll probably try rice and play dough soon as well. And pudding finger painting. And hopefully, some good old fashioned digging in the dirt.