Okay, I studied
coach.com's frequently asked questions and the only leathers it says that a damp cloth can be used on are pebbled, vaschetta, and patent. So I still didn't know if a damp cloth is okay to use on "regular" leather like my ergos.
I finally got my answer from this website:
http://www.designerhandbags101.com/purses/designer-purse-care.aspx
It says to wipe off leather purses with a clean, moist cloth before applying moisturizers.
I take that to mean any and all leathers, as long as the cloth is lightly damp, why not?
It makes sense not to apply moisturizers on a bag that has dirt (seen or unseen from salty sweat/skin oils) until cleaning it first! Salt/dirt is leather's worst enemies.
So I guess I answered my own question, then! Maybe the tPFers here do not sweat like I do, they "perspire" so this question seemed revolting! hehe