The RTA has five different sets of rules about this. In some cases, the landlord can sell, keep or throw away property the tenant left behind. In other cases, the landlord has to store the property so the tenant can come pick it up.
Which rules apply depends on how, when and why the tenant moved out. If the landlord does not follow the rules, they may be held liable for the loss. For more information, see the brochure: Property Left behind When a Tenant Moves Out.
Source: www.sjto.gov.on.ca