Old outhouses (no longer in use BTW

). If you can locate where an old outhouse used to be, then see if you can get permission to dig it out. I saw an episode on the History Channel where a guy located an old house site where a paved lot now stands out in Cali. He, don't ask me how, somehow got permission to break the pavement where he determined through his years of bottle hunting where a potential outhouse could have been, and was right on the first attempt. Found several intact bottles from 3-7 feet down, including an old champayne (sp?) bottle unopened, along with other liquor bottles, perfume, medicine, and condiment bottles. Seems the owner liked to sneak out to the privy for a snort now and then based on the amount of liquor bottles he located. Makes you wonder where the owner hid it from everyone else? Folks used to drop all kinds of stuff in those things and/or loose stuff as they stripped down. Dig slowly as you don't know how deep it could be or when you'll come across an item. Also MD it for metal objects; good place for coins lost by accident.
Another spot folks would throw away bottles would be in old wells, but there's a safety aspect in recovering items from them - take extreme caution and have someone else nearby just in case.
Old home sites. If you can find one, usually near by is where they dumped their trash. From the house location, start a circular pattern and continue to expand the area; its usually not too far away. Try to locate a metal rich area with your MD, usually iron objects from the house are there, and start to dig down, again slowly. If you're lucky you could come across an old house dumping site with glass and bottle frags on top of the ground, or possibly an old bottle still intact. That's usually where the rest of them will be.
Lastly, I've hunted CW sites and found period whiskey bottle frags right under the leaves as I'm digging a signal. If you're lucky in a CW era camp and come across a fire pit or hut site, those are also good spots. Intact dinner ware, ink wells, condiment containers, and whiskey bottles are common if you know what you're doing. Unfortunately people start to dig a signal from the MD and accidently hit and break a bottle. It's a chance you take, but folks do retrieve them intact if they feel they're into a fire pit or hut and dig carefully and slowly.
Did I mention dig slowly?