to privy dig, you look at old maps, such as Sanborne. Find out where the privy was in relation to the house and go door knocking.
Bring a tarp, a bunch of boxes/milk crates and if you have any, 55gallon drums... cut sod carefully, lay in order on tarp. Probe to check depth. Commence to digging.
Put bottles in boxes/milk crates, dirt goes into 55g drums or on the tarp. if you hit a dead spot, probe again and keep digging.
Most privy will have wood shoring or brick/rock shoring for the "hole". When done, refill and tamp down fully, replace sod correctly, use garden hose or bottles of water to hit the seams, make sure owners are happy with your landscape job, shake hands and go home happy.
I started digging the farm that father-in-law grew up in. It's been in his family since the mid 1800's. outside of some obvious dumps.... old wells filled with bottles, trash pits all over, a 300yd ravine 15yd wide of nothing but bottles and such 2-3' deep....there were 4 privy sites. One that's there now from the 30's-50's and the rest were the old ones. Luckily, I don't have to be neat when I do this. It's all in the woods so I can just pile it up and fill it in when I'm done.
My 11yr old is my digging partner. We ripped the 2 holer down and cleared it. The walls were shored with logs...That's a good sign. We dug one hole and used the other hole as a set of stairs so we'd have a way back up. Haven't found much of decent stuff yet. Marbles, china pieces, some toys, ton of beer bottles....was a bit disappointed til we hit the bottom of the logs. Thought we were as deep as we were going to get.....My daughter asked if we could go another hr. We dug and bam..hit another shored wall and more black ashy sand...had to stop, but at least we know there's stuff down there...
here are a few pics of the ravine we started on: front, middle, end and a closeup of the small area we are only started at.