Happened to probe these three nice pieces of glass out of swampy areas within the past week. In order of appearance: CD 742 in Blue, CD 152 Hemi with large 7 on dome, Bright Green, and CD 145 G.N.W.TEL.CO. in a Medium Purple. All were about 4-6 inches down and at least one required about 10 minutes of pulling on roots and wiggling the insulator before I could free it from the mud (the GNW!). We use pitchforks (with all but the two center tines removed) as our main probes, as well as long screwdrivers, root cutters, gloves, etc. for these hunts on land and, umm, "sea". Some of you folks who think there's nothing out there in your area may want to start checking any swampy areas along your local lines, as the linemen are likely to have tossed glass from any nearby pole there... who would know but some crazy nut 100 years later who is actually looking for it??!! You'll want some rubber boots too, and probe before you step, not only because you might push one deeper, but you might get a nasty cut from any broken glass. Good luck!