Mildew on window sills - charge tenant?

[Andrew S.]

Hey BP community, I have an inherited tenant who moved out of a single family home. They left with a decent amount of mildew on the window sills. I'm in Montana and the windows are good double pane vinyl windows. I assume the window sill mildew is a result of cold outdoor temps, maybe not great wall insulation, keeping the heat turned down when they were away building their house and/ or not venting the bathroom during showers.  I have an estoppel that says there was no maintenance issues 6 months ago when I purchased it. A few months ago, they mentioned mildew on a baseboard after leaving a wet towel there for a while. It'll probably take me 4 - 6 hours to clean up. Is it worth charging them ~$150 out of their security deposit to clean this or should I just move on? Should I charge more, less, or nothing at all? Sounds like other forums would suggest to move on and not deal with any future legal battles about mold being the landlords responsibility. Thanks, Andrew