Mont. Code Ann. § 70-25-201

(3) (a) Cleaning charges may not be imposed for normal maintenance performed on a cyclical basis by the landlord as noted by the landlord at the time that the tenant occupies the space unless the landlord is forced to perform this maintenance because of negligence of the tenant. Additionally, cleaning charges may not be deducted until written notice has been given to the tenant. The notice must include the cleaning not accomplished by the tenant and the additional amount and type or types of cleaning that need to be done by the tenant to bring the premises back to its condition at the time of its renting.