Volcanic ash will stay on bare lubricated surfaces. It can go into many conventional seals, go into the engine gas path or go into the air condition system. It is possible for the ash to go into other openings on the airplane. Bare lubricated surfaces that are known to be contaminated with volcanic ash must be cleaned and relubricated . Do this as soon as it is possible to prevent unusual worn areas to the parts that move. Some of these parts are the inner cylinders of the landing gear shock strut, and hydraulic actuator rods. Also there are stabilizer trim and flap screw mechanisms. You must monitor parts that turn or slide for signs of volcanic ash related damage. This procedure must be done as a program that follows if initial damage was not found.