Yes, take a paper punch or ice pick or walk on it with crampons or golf shoes - put a whole bunch of little holes in the baggie. Wet the sponge and wring it out - it usually stays damp for up to a week inside the case. For normal guitars I just put the baggie in the headstock area of the case, for extremely dry guitars I put it inside (and a second one at the headstock). It is pretty hard to over humidify unless you live in one of those areas that people have mentioned where it is over 50 percent INSIDE. For most of us the problem is winter when we heat our homes.