Raspy, how long have you been able to keep a vacuum in a ziplock? I have used your method to pull a vacuum in a ziplock, using a vacuum pump not a shop vac, but i have not been able to keep a ziplock with vacuum in it for more than a few days. What brand ziplocks have you had success with? And yes i know that a plastic bag will not hold a hard vacuum for long but the ziplocks that i have tried have not held a vacuum at all.