Washing machines and dryers only need a couple of basic cleaning procedures. Always follow the manufacturers recommendations when cleaning the lint filter or under the agitator.
If gum or grease deposits onto the interior try to rub off with a soft cloth and mild detergent. Failing that, applying a small amount of degreaser or gum dissolving chemical onto the area affected should loosen the deposit. Never use abrasive cleaners or pads and always rinse completely.
Of course dryer lint screens must be cleaned before each load to ensure drying efficiency. For a more thorough cleaning, mild detergent and water works well. Completely dry the lint filter before using. For deposits on the dryer interior, usually caused by melting items from pants pockets, use a mild detergent or stain specific cleaners very sparingly. Afterwards wipe again with a damp cloth and let the interior dry. Do not use abrasive cleaners.
Dryer vents and pipes need regular cleaning to ensure full airflow. Often it is a simple procedure to remove the pipe and clean it out. A vacuum works well. Be sure to re-attach the pipe securely. If you are in doubt consult an appliance expert.
Use mild detergent and a damp sponge or cloth to clean the outside of the unit.