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How to Wash Dishes


Order of Washing
This defines the order in which the items (a general term covering all cutlery, crockery, pots and pans) are selected.
The order of washing, through experimentation, is:
Cutlery, cleanish plates, dirty plates, pots and pans, any very dirty item.
Note that any item can be demoted to the bottom of this list simply by force of its disgustingness.
The Pile
A pile of dirty items
The Draining Board
An organised set of clean items
The Soaking Stack
This is a pile of items held within the washing-up basin.
The Current Item
This is the item currently being washed.
The Queued Item
This is one item which is washed in parallel with the Current Item. The difference between the operations on the Queued Item and the Current Item is generally one of degree: the Current Item undergoes concentrated washing; the Queued Item is lightly prepared for the rigourous Current Item operations.

Behavioural Rules


The Current Item and the Queued Item are both washed. This involves completing a series of acts. The item has not been cleaned unless all of these acts have been completed. Some acts may be performed on a Queued Item, some acts may be performed on the Current Item, some may be performed on both. Acts vary according to the item. Acts should follow the order in which they are listed.


  1. Dipped and shaken under basin water - Queued, Current
  2. Areas of uncleanliness observed - Queued, Current
  3. Unclean areas scrubbed clean - Current
  4. Re-dipped - Current
  5. Rinsed under cold tap - Current

Pots, Pans, Cups, Mugs

  1. Dipped and shaken under basin water - Queued, Current
  2. Areas of uncleanliness observed - Queued, Current
  3. Handle (if any) of item scoured - Current
  4. Outside bottom of item scoured - Current
  5. Outside sides of item scoured - Current
  6. Inside bottom and sides of item scoured - Current
  7. Remaining unclean areas scrubbed clean - Current
  8. Re-dipped - Current
  9. Rinsed under cold tap - Current

Main Program

  1. Clean basin.
  2. Fill basin with hot water. When almost full, add detergent.
  3. Now drop five to ten pieces of cutlery from the Pile into the basin (depending on size and dirtiness). This will form your initial Soaking Stack
  4. Apply General Rules continuously until all items are on the Draining Board

Other observations

Procedures may vary according to local cultural norms. Japanese delegates had a number of criticisms .

Kirsten from Edinburgh writes on 5/9/99:

Do the glasses first, followed by other delicate glass items. Follow these with mugs, plates, dishes and other china before moving onto cutlery and pans. Cheese graters should be left to soak for at least 2 days. Porridge pans should be soaked in cold water for a couple of hours then scraped out with a plastic spoon before being washed. Scrambled egg pans should just be thrown away.

A more finely defined ordering system: thank-you. The whole "Wash Up vs Throw Away" decision mechanism requires more investigation. Other possible cues for deletion may be: equipment involved in toffee production, Woks post oily burn-fry meals, and any mug supporting a long-term slime mould colony. - d.

David Cridland had some unspecified objections to the ordering of the general rules, but helped clarify when exactly washed items should be thrown away with this C++ code fragment.

Miranda Mowbray asks if there might be a lock condition in the original algorithm? Her paper asks the question: "if the washing is being processed by two or more washers in parallel who both try to pick up the same item from the Soaking Stack? If the item is big it can be washed by more than one washer at once, but if it's a teaspoon you might get a tug of war. (Parallel processing is my favourite method of washing up.)" It's true that the algorithm is neither thread safe as it stands, nor is it re-entrant. Which is to say, if you leave the washing up, and then someone else joins in to help you, any of the stacks could get corrupted.

The security implications, likewise, have not been sufficiently explored. All of these points may be cleared up when we have a formal proof of the algorithm.

Gerard Watts writes: "I find an acid rinse (a squeeze of lime or lemon juice in a bowl of hot water) gives plates etc a nice squeaky clean feel. It also has an astonishing effect on the brass plug hole.". This may be the original ur-concept behind why so many detergents stink of lemon, sort of like why we have Easter eggs instead of chocolate jesuses-on-a-cross. If you get what I mean. I may be wandering off topic here.

Russel F. Dickson notes the benefits of parallel washing (him and his brother), although notes that the second server frequently suffered from "allergic" reactions, resulting in a loss of a server for at least 25% each day. "Any cures or preventative treatments would surely be of benefit to mankind.". He also goes into some detail regarding Egyptian methods of washing up, which involve a small mug of washing up liquid, "definately not clean despite presence of detergent.".

Chris Gray is concerned to attach the following patches:

  1. Baby items should be first in the order as they have a less well developed imune system
  2. No mention is made of which implements to use e.g. nylon bristle brushes are good for cleaning cheese greaters and pans with sticky (but not baked on) residue (porridge, baked beans). Sand paper can be used for the top layer of crust on some stubborn deposits (power tools should not be used in conjunction with water)
  3. draining racks are great but must be loaded top first but car must be taken not to destabilise them by raising the center of gravity too much.

Any comments, corrections or additions to danny@spesh.com. I'm particularly concerned with potential deadlock conditions in the washing procedures, and additional information on exotic items.

Last modified: $Date: 2005/04/17 13:28:00 $