You don't want to mop and wash off your bark.
those that use a string mop often sling or slosh it on.
A good quality spray bottle works well,if you don't have particles to clog the holes.
A spray ,like apple juice,can carmelize some and increase bark some.
I am more prone to spritz ribs and leave the rest alone.
Very large ,long cooking cuts are the exception.
But,that's just my approach.