You should open it every day in the beginning. Some ppl will say more than once, but if you hung them the right amount of time (depending on bud size and density), once should be enough. After about three weeks give or take a few days, it will be done. I usually open them up and let the A/C pulse through the jar for 5 seconds. Nice cool dry air. Of course each time you first open them up, take a sniff and if you get a lemon ammonia whiff, you have mold in there somewhere.