So I looked down at my shoes the other day and I noticed the outline of what appears to be some sort of stain. My problem is I have no idea what might have caused this. I've looked at photos of various types of shoe stains and I'm still not confident what type of stain this may be. I've already found plenty of helpful advice for removing stains from leather shoes but I'd prefer to know what type of stain this is so that I can select the best method for removing it. Any ideas? Thanks!