If you have trouble unscrewing them use a wash cloth soaked in white vinegar and wrap it around the element for 24hrs.

It's a whole house rewire including new service drop by the power company - - very expensive - - but mandatory for safety as the cloth insulation has rotted away.Plaster was applied over a lath base and you strip the walls & ceilings down to the studs to replace with today's wallboard.Bet you had no idea of what you've gotten into - - sorry to be the bearer of bad tidings.

The first floor contained a coffee shop, yoga studio and gym.

Most people looking in from the outside think you have stacks of cash and spend your days shopping for high end clothes.

Walls or damp to touch, and some clothes are now moldy.

Once you add-in the cost of utilities (especially heat), furnishings (couches, tables and chairs, beds, sheets, towels, table cloths, pots and pans and plates and silverware, napkins, toilet paper, TV's and radios, washer and dryer and refrigerator - yes, it's common for a long-term SFR not to include a washer, dryer, or refrigerator - etc, etc, etc), plowing/lawn/trash (or HOA fees), cleaning, extra repairs and maintenance (I promise that a long-term house renter takes better care and causes less wear and tear than a revolving door of vacation renters), turnover management and screening, etc, etc, you are not making any more with the vacation rental than with the long-term SFR where the tenants pay all the utilities (possibly with the exception of water/sewer), and take care of the lawn and snow, and provide their own furnishings soup to nuts.

The unit is still fully furnished, including clothing and food but no one is staying there.

I tell them that rent is the very first thing that they need to pay out of their paycheck, because without a roof over their heads they don’t have any private place to lay their head, to change their clothes, to take a bath, to go to sleep or any place to STORE THEIR STUFF!

That is where retailers struggled the last 10 years figuring out how to make all the pieces work properly.90% of almost all retail closures last year where clothing and furniture  store related.

I suppose since you're physically living there you can monitor this a little bit, but the cost/time/effort it will take to repair your broken laundry machines and worry about strangers being invited into your building to wash their clothes versus the amount of money you'll make on it is, in my opinion, not worth it.