Patricia Nash Discovery Minori Satchel

I purchased this from an online shopping channel and did not remove the tags. There are white stains on the bag (pictured) and I think it happened when I was moving it around in my closet. I'm afraid to use anything on it as I don't want to make it worse. SF. Pets do visit but they are not allowed near my bags. It's a heavy bag due to the leather and rivets. Comes with crossbody strap and dust bag. 13.25" length x 10" height x 5" wide.