After the washing has been finished, open the washing machine door and leave it open until the next wash. By leaving the door open you let the machine dry out inside and this will prevent two things from happening. Firstly the door seal will not get so mouldy/smelly and secondly and more importantly the machine will not corrode on the inside.
Even tho washing machines are meant to get wet on the inside they should be dried out when they are not in use. Insides of the washing machines are made from metals/alloys that are corrosion resistant but not when they are constantly kept in a moist environment.
In the picture its one of the machines we had to repair. The customer constantly kept the door closed and the part that holds the shiny drum inside the machine in-place corroded and the drum has collapsed. This is also a costly washing machine repair that could have been prevented.
Remember to leave that door open!