What can I legally do with abandoned property?

I live in Colorado. My husband and I let a good friend of mine move in with us. He lived with us for about 1.5 yrs, rent free. He never paid rent, or any money for food or anything. We all had a minor disagreement and he walked out and NEVER returned. He hasn't even come back for clothes. He left ALL his stuff here. That was 3 weeks ago. I sent him a email a week and a half ago telling him that he needed to remove his things by the Wednesday (last week) as my mother in law is moving in with us. First he asked ME to pack his things for him and leave them outside, I told him I don't have time nor the desire to pack his things and to come get them, he said he would be here Wednesday (again last week). He never showed. I need this room cleaned out ASAP. I just found out that he is now living in Texas! So I need to know what I can do with his things. He has no job, no vehicle, so I know he has no plans to come after his stuff any time soon. So what are my options?