heres what ya do, go out in your yard, get a tape measure, then ya write out a big formula, like from your door to your yard, put like 33f, 12l, 11b, 2r, 6l, 2f, with a bunch of other #'s. f=forward l=left r=right b=back, and all measurements are in feet, do this according to the size of your yard, write down the measurements, put them in your banking info or somthing where you know you wont loose it, also save it in an adress book on hotmail or somthing, if anyone sees it they will have no idea what the hell it is, but you will know its the map to your stash. serriously, its fool proof if your really worried, just gotta make sure it grows back up so u cant tell. and also, when u remove the top layer of grass, dont just hack it out, cut it away like a piece of sod like in a square or somthing, just hopefully the moles dont get it! haha we have moles bad here. good luck!