I did a "restoration" on a friend's washer & dryer. They were included with a house she bought.
I put two bottles of CLR in the washer and let it sit in the (front loader) tub for half a day.
Then let it start the drain cycle and stopped it so the CLR could do it's magic on the pump and hose assemblies.
Then let it run a full "load" with hot water to wash it out.
Then poured in a gallon of vinegar and did the same thing with that.
And finally put in ten cups of baking soda with hot water and let it run for half a wash cycle then turned it off and let it sit overnight. Came by in the morning and turned it on and let it finish the was, rinse cycle.
After all that the built up sediment, calcium, and horrible smell of mold were all gone.
It smells, cleans, and after a little Menzerna love, looks like a new washer and dryer.
All I did to the dryer was to buy a new dust trap filter and wipe the entire inside of the machine out with a wet towel to grab all the lint. Also cleaned out the exhaust ducting too.