Oswald G. Scherell was a well known - or even "the leading" - Prussian gunsmith in the early 20th century, but the origin of Sherells as gunsmiths goes back to 1834 (or possibly earlier). Soon after WWI he developed and marketed Shaftol, even now the leading German stock oil. Known from the 1930s are guns marked "Waffen Scherell Berlin" (Waffen = arms). Some years ago Shaftol was offered by Hans Scherell, Mainz, but is now owned by Klever (Ballistol).
With kind regards,
Jani