If you don’t approach this in a business like fashion you will be the one that suffers.

As soon as stainless steel came into fashion I thought they were already outdated things that are going to be dated any day now. 

So, even though I got them to move out in an amiable fashion, I think they could sense that if they didn't, I'd be happy to nail them to the wall LOL.  

Just to add....the security deposit isn't identified as his or hers, so for you to split in any fashion, even if you wanted to, is a recipe for you to be taken into court by one, the other or both. 

They never get back timely fashion, so send a few reminders.

When was the last time you ever had a window break itself in that fashion in your home? 

You could always put artwork up so it doesn't look like a blank space when you're showing the unit.The bathroom will look really good for $500 or under with these updates. 

If debt could be used in a similar fashion in the stock market then the stock market would clearly be better, but you can't.

I don't believe there is such a thing that could possibly replace good old fashioned personal screening. 

Send him a letter on the disposition of the security deposit in a timely fashion according to MA Landlord-tenant law and see what happens.