Thanks for your advice!
You don't really need to get rid of any old glue on your sponge and blade. The new rules prohibit the presence of VOCs in the racket. A week or so after gluing, any VOCs that might have been present should have evaporated to the point where they are no longer significant, and your bat will be legal, even if you had used illegal VOC containing speed glues. That said, it's probably best to stick to using water based VOC free glues in the future.
However, if you just want to get rid of any buildup of glue that is sitting on the sponge or blade, some players simply rub it off with the palm of their hand. Others find using a little solvent (such as acetone, nail polish remover, or even a little more glue!) to soften the glue to allow it to be peeled off also works well. But you really only need to do this if you were speed gluing in the past and had a big buildup of glue on the sponge, that was preventing any new glue from soaking into the rubber.