Muhle is German for mill and OO is a grade of flour indicating a flour bag seal from Danzig (Gdansk). Unfortunately the first letters of the name are missing.
From Paul Cannon, "I think this seal relates to a significant mill in Danzig (German for Gdansk). Based on similar examples [GROSSE] MÜHLE / H BARTELS & Co / DANZIG see Euro-Plombs. The following includes links to the history of the mill (in Polish) Plomba ołowiana H. BARTELS & Cie - Danzig, My Virtual Museum."
