Obviously it's necessary to keep some powder dry for the unexpected, but I also hate seeing good money sitting in cash not earning anything.

The one I mentioned was for powder ridge.  

That being said, there are tax benefits to the debt, and often having dry powder so you can take advantage of deals/ opportunities in the future leaves you better off than if you had a paid off property. 

Try a magic eraser first with plain water, then Bon Ami or Barkeepers Friend scouring powder with a regular sponge.

And by putting a revolving LOC on the free and clear property the investor keeps their powder dry in case the next perfect property comes along.

I've read on this very forum of a powder that actually works.

The world is a bit of a powder-keg and primed for flash-crash event makers.

I'd offer the Tenant a movie pass and see if he'd take a powder during showings.

Right now keep your powder dry.

I even dust the joints with baby powder to get them to slide more easily.