All owners of taxable personal property are required, annually, to file a Personal Property Declaration Form M-15. If I move out of Middlesex County or sell an item of personal property, will my tax bill be prorated?Middlesex County does not prorate personal property. Taxpayers should use these forms and guides to apply for local tax abatements and exemptions and file property returns. Exemption applications must be filed with your local assessor's office. See our Municipal Profiles for your local assessor's mailing address. A single personal property assessment is made for all taxable personal property of the owner located in the city or town. 2. Property Tax Reimbursement Forms (PTR) May Be Filled Out on the Following Days and Times. Use the free New Jersey Online Filing Service to file your 2024 NJ-1040 return. It's simple and easy to follow the instructions, complete your NJ tax return,.