Best way to run down phone battery?

[Black]

I bought a spare battery for my Note 5 and would like to run it down all the way tonight if possible (need it fully charged in the AM.) What's the best way to do so? And is this really helpful or does it fall into the myth category? There's about 50% left on the battery now.
Or-- is it OK to charge it now and then let it run all the way down sometime in the next day or two?