Myself and one other person are on a written lease agreement. Our third roommate was on a verbal lease agreement. He stopped living at our residence almost 4 months ago and left all of his belongings. He will randomly state he wants his stuff back, and we say we want the $700+ he owes us. Can we get into trouble to just dispose of his things as we wish?
Thank you.

You can not legally hold his belongings in lieu of the rent. You can sue him but your verbal agreement may be difficult to substantiate in court. He might try to say there never was any agreement. If he asked for his belongings and you refused, due to the rent, you can not pitch his stuff. Do the right thing even if he isn't doing right by you. Send him a certified letter saying he should pick up his belongings by a reasonable date. After that date his stuff can go to the curb.