I washed my bag in the washing machine. It was a Hamptons Patchwork Weekend Tote. It was 'REALLY' dirty, and baby wipes were not cutting it. I used a little woolite and warm water, on the gentle cycle with a drip dry spin cycle. I came out well. ( I have a front loading washer, i don't think it would have worked as well with a top loading one.) I let it hang dry and put a little leather moisturizer on the handles and the leather trim.
It came out good. No obvious damage to the leather or anything. Not that I would just throw my bag in the wash because I felt like it, but it is good to know that it didn't get ruined.