can assist with removing all of the bottle caps from what you perceive to be the best areas. Turn down the sensitivity of your favorite detector / small coil and see if you can remove 10 or 15 bottle caps in 30 min. If they are relatively shallow, electronic pinpointing than removal with a screwdriver should be very quick. Clear out that shallow stuff than increase the sensitivity and take out the rest. It takes time - but accurate pinpointing makes quick work. A helper can get up and down quickly.
rich