What about using the DE along the outside boarder of everything? Would that help keep things out? I was told DE was great to use (I bought a small jug for 20.00!) I got it also because we have an ongoing flea battle (took a dog in that had been dumped on the side of the road, and he was loaded. Never had fleas in that area in the 7 yrs we lived here until he came (sadly, he passed from bloat last fall), but now it is an ongoing issue, I cannot get rid of them! (And I have 4 dogs, so not good!) I was told to use the DE directly on them, as well as in cracks, crevices, furniture, etc. (Sorry to go off topic, anyone ever used it for fleas?)