I too have had a few lost evenings in trying to decipher the darned notes. My latest attempt was at a Low German Dictionary:
http://www.mennolink.org/doc/lg/ but it was of no use with the notes I was working with. I have tried online translations in Low German, High German, Dutch, but have not had a good success rate with those from Germany. The Austrian ones were simpler, as I guess they had fewer dialects, but I really don't know.
One guess I have is that as they were printed locally, then the dialects were likely containing colloquialisms (sp?) and those may not be in the dictionaries. I used to work with a guy from Taiwan and English was his 4th language, adn he would get stumped on some terms a lot - they just made no sense the first time he heard them. Imagine trying to look up Ya'll, howdy-do!, or "I gotta' get me a mess o' them greens" in a dictionary - - I think that's where some of them are lacking. My latest purchases were surprising as they had a company name on them that I thought was something else.... I would never have found out if I hadn't just plain typed it into google and had it come up - Still in business!
I think I'm on year 2 with "Wat Mutt, Dat Mutt" - My guess is that it is something like 'what must be done will be done', but I have no real idea.
It is also very hard to read the older german script in some of them. I was discussing this with a friend of mine whose mother is from Germany, and he said that she never learned the old script, but that his grandmother can read it with ease. I might take him up on an offer to have him get her to try her hand at some of my more difficult ones.