That is how they are suppose to work. The media that the formic acid is in is designed to slowly release Formic acid over a couple of weeks. What is left over is basically inert material that just slowed the release down. These pads can be composted. (it is all in the faq on their website). You can leave them in place for a while, no need to pull them quickly.I checked just a handful of my hives and all of the formic pro pads disappeared leaving just the paper shreds behind, except for this one that left the entire dried up pad! What's up with that?