Tenant's lease expired, hasn't completely moved out

[Greg Walsh]

I own a rental property in Connecticut and have yet to find the legal answer to my specific circumstance. I have a tenant whose lease expired 30 days ago, they moved almost all of their stuff out last weekend but some remained. I naively gave them their security deposit back without them giving me the keys.  They said they would come back to clean the apartment a couple of times but are not doing so.  Do I have the right to retake possession of the apartment, get it ready to rent again?  I think I'm supposed to mail them notification that in 10 days I will put their stuff in storage for 30 days, but I don't know if I can do that now or if I'm supposed to wait a prescribed amount of time after they started moving out.

Thank you