The aircraft in the fleet I fly all have dusting brushes (an ordinary 1 inch paint brush) attached to the FD sidewall by Velcro. That, along with the wipes, is normally sufficient to make each FD as clean as any individual pilot wants it. Rubbish is never left by preceeding crews -simply an unwritten, unspoken, culture. Prior to fitting the brushes pilots would generally carry their own paint brushes -if concerned enough.
