Q: "Can we use our deposit minus any cleaning/damage fees to help pay the last months rent?"
A: Nope. Minnesota Statutes prohibit it.
"504B.178 Interest on security deposits; withholding security deposits; damages; limit on withholding last month's rent.
Subd. 8. Withholding rent. No tenant may withhold payment of all or any portion of rent for the last payment period of a residential rental agreement, except an oral or written month to month residential rental agreement concerning which neither the tenant nor landlord has served a notice to quit, on the grounds that the deposit should serve as payment for the rent. Withholding all or any portion of rent for the last payment period of the residential rental agreement creates a rebuttable presumption that the tenant withheld the last payment on the grounds that the deposit should serve as payment for the rent. Any tenant who remains in violation of this subdivision after written demand and notice of this subdivision shall be liable to the landlord for the following:
(1) a penalty in an amount equal to the portion of the deposit which the landlord is entitled to withhold under subdivision 3 other than to remedy the tenant's default in the payment of rent; and
(2) interest on the whole deposit as provided in subdivision 2, in addition to the amount of rent withheld by the tenant in violation of this subdivision."
Source:
http://www.revisor.leg.state.mn.us/stats/504B/