My roommate left her belongings in our apartment which she no longer pays for, what do I do about her belongings?Are they now mine?

I would try to make contact and ask for the items to be removed. Failing this, perhaps take the items to a charity shop, whereby some benefit to others will be derived.

put them in a storage building pay the first month then send her an email stating where they are and how much she owes you for the first month storage. Keep the receipt because if she doesn't pay you can take her to small claims court for the month of storage, your moving expenses for moving them to storage, time etc, and any bills you were left to pay since she skipped out on the lease (if she didn't give you notice of her moving and / or defaulted on a lease and other bill obligations.)

IT's a win/win, if she doesn't pick up her things from the storage they will sell them and you still can take her to court for your $

Call her and tell her if she doesn't pick them up within a week they will go in the dumpster.

Use your cell phone so there is a record of your call.

Take them to a police station, and after a certain amount of days if they are not claimed, they are all yours....well! thats the rules here in the uk.

could you contact her/him? if so ask her/him what they want doing with them. if not then there yours to do with as you see fit! :-)

I sold my old room mates stuff on Craigs List. What I couldn't sell got thrown in a dumpster behind a supermarket.