Clothes, bedding and other items get dirty whether there is a disaster or not. You will still have to do laundry after a disaster. Planning for that is an important part of your preparedness. Getting sheets and jeans into a bathroom sink and scrubbing them by hand and getting them dry afterwards is very hard work.
Anything that you can do to make laundry easier after a disaster is going to improve your chances of survival. If you do laundry efficiently, that will give you more energy to get food and water, for example. If you do not do laundry after a disaster, you will be more likely to get parasites or disease. That can be a threat to your survival.
Many hardware stores still sell washboards. This is a corrugated piece of metal or glass in a wooden frame. You rub the items to be washed on the washboard after wetting them in soapy water. It does not require a lot of rubbing to get the laundry clean. One rub in each area of the piece of laundry will be enough. This is more scrubbing than happens inside a washing machine.
If you rub the piece of laundry on the washboard too much, you can wear holes in it and make it wear out much faster than normal. Restrain yourself in case you can not replace the item. rubbing too much robs you of energy to do other things as well. Making yourself unnecessarily tired is much like throwing away food. It required eating food to give you that energy.
You will probably get your clothing dirtier after a disaster than you normally do. Because of this, you may wish to lightly scrub the especially dirty areas a little extra. Apply a little extra soap on those dirty areas if you can spare the soap, or let the whole item soak a little longer, before you do the extra scrub.
Another way to plan to do your laundry is to use a 5 gallon bucket or other large container, and a clean toilet plunger for a "washing machine". I have not tried this yet, but just bought a new toilet plunger. I also got a long dowel about the diameter of the one that came with the plunger. This is so that I will not have to bend over so much when washing with the plunger.
I already have a washboard and am quite good at using it. That does not mean I like using the washboard.
This post got too long, so I am cutting it in half here and will publish the other half tomorrow.