Been there, done that, bad idea. Lol. Picture toddlers wandering away from the sensory table with spoonfuls of colored rice and then it spills everywhere. You turn around and toddler 2 is doing it too. And the others etc. if you have A LOT of time and patience then go for it. You will have to spend a lot of energy "training" them and cleaning up.

Mind you after saying all that even I have been considering letting the two older girls play in the sink with play dishes etc because we are getting tired of winter too.