Fireplace Not Functional

[Aaron Lancaster]

I purchased a duplex earlier this year in a B-class neighborhood. There is a wood burning fireplace in each unit, but after having them inspected, neither are safe to use and need a total of about $1,500 to bring them up to code. I'd like to simply tell the current tenants they're not functional and that they're not allowed to use them. However, there's always the risk that they will use them anyways without my knowledge.

Nearly every other duplex on the street has a wood burning fireplace, so I'd prefer not to cap it / block it off in case I ever want to sell it.

 Should I go ahead and spend the money to make them functional and then still tell them (and put in future leases) that they're not be used? Or should I just leave them as is and tell them not to use them?