Hung one of these in our mudroom a while ago, which goes out into our garage. Forgot about it until today, and, yeah, apparently, it works! (You can see that the bottom part- the bag- is filled with water.)
I just hung a new one in there, and put one in the garage as well. If you have an area that can get damp, I recommend these! They do have a bit of an air-freshener type scent, but it's not bad- more like a dryer sheet.