Digging in the muck...

[kleinkaliber]

Years ago when folks were digging the Benecia mud flats they would use apple bins. These were 4x4x4 wooden boxes, or close to that size. They would take the bottoms out and then sink them down in the hole as they dug to keep out the goo using the sides as shoring. Then it was just a matter of mucking out the goo and water. Many great bottles were found this way. I never saw it but heard this is how they did it. Good luck.

This is what I've been told as well, when listening to the older diggers in this part of the world talk about the great digs of the past. Google Benicia glass.