I have 15-20k in damages.

In my state (oregon) you can only charge a tenant for damage to something if it still has “ useful life”   so I would check your state laws regarding this....  

I already know there is damage on one side that needs repair and am willing to forego charging the tenants for damages if they vacate by the 20 days with no further damage from the time of the inspection.

I dressed up pretty silly for Independence Day!

The house is uninhabitable, full of trash and fire damage.

This was something that simply lacked pro-activity… It costed me more money to fix the copper pipes as well as the damages that had occurred to the property.

This was caused from a drainage issue that was addressed only a few years ago, but the damage from years of water is done.

This encourages them to pay the last month of rent and leave house clean so that they get their large deposit back.If they get behind or break the lease, this extra helps offset what they owe plus any damage or cleaning you have to take care of.It is a small percentage of the time that someone turns in a 30 day notice and leaves the place clean and undamaged to get their deposit back.

Is that damage from the hurricanes?

The house had 100+ feet of sill/termite damage, rotting joists under the bathrooms, no recoverable plumbing, no recoverable HVAC systems, no recoverable interior wiring (original knob & tube), and "dead" plaster falling off half of the walls.