I packed some wheat and oats in large mylar bags for 5 gallon buckets and put in 4-500cc O2 absorbers each. Most of the bags tightened up, but I have 3 that still have some air (there's a definite "pillow" of air). I actually already opened them up, put new absorbers in, and resealed; but for some reason I'm not getting enough air out I guess. Do I try again? Any ideas of what happened? Thanks.