- Convert epub to epub in Calibre, removing the spacing and margins in the "look and feel" section
- Open the resulting file in Sigil
- edit the stylesheet in Sigil to make sure that all references to "leftmargin" are set to "0"
- save the file in Sigil then open it in Calibre again
- use Calibre to convert to mobi
Takes about 5 minutes per book. Not a major deal unless you're converting a lot of stuff
- courtesy of TeleFunken @ EG