In some states where its "somewhat" legal your allowed up to 25 grams. Punishable by a $100 fine. If you add a pipe, it becomes a felony!! Also you have no idea what was smoked through that pipe. Could be PCP, Hash, Crack
and they can charge you with just the residue left in the pipe...

Be safe people this is serious !! If a cop pulls you over after you hunted one of these things and finds it. (Yes you could say you dug it and its filled with dirt but...) its
entirely up to the cop if he want's to charge you and test it and charge you with what's inside...
Keep @ it and HH !!