Before varnishing the rest of the interior, there are a dozen or so doors and hatch covers and a few pieces of trim to be coated with polyurethane. (In case you were wondering, there is such a thing as mono-urethane.) Depending on one's state of mind, this work is either meditative or tedious.
What do you do when you don't have a small enough brush to get into the holes? You cut down a foam brush.