Baking soda and white vinegar work great for descaling and cleaning washing machines.
If it's a top loader washing machine fill the wash tub with water and then add some baking soda and vinegar and then run it through a wash cycle.
Once the wash cycle is done you may have to wipe down the washing machine drum with a towel to remove any residue.
For a front load washing machine put the baking soda in the tub as well and put the vinegar in the detergent dispenser and then let it run through a normal wash cycle as well and wipe the washing machine drum down as well.
If your washing machine door seal is smelling you can stop the washing machine door seal from smelling by spraying some vinegar and water onto the rubber seal and then wiping it down.
Vinegar and water will get rid of the odor that the washing machine door seal has.