I decided to give Ask Jeeves a try on this (why does a "spit shine" work) and came up with the first document below (among other things, two of which are included as well). It seems water does play a part in the shining process described but there is also bootlicking and lace sucking involved so I am somewhat skeptical.

Here is another site that says it takes 1-1/2 hours per boot: www.cadetstuff.org/how_to/200201_elliott_bulling.htm

Kiwi sells "Parade Gloss" shoe polish that "Contains silicone for a spit shine without the work."

A BOOTBLACK GUIDE TO THE MILITARY SPIT SHINE

(This was given to me by a man whom loves his boots. I sincerley thank him for allowing me to share it.)

Most bootmen get off with hands-on physical tightness with boots. Whether your own, laced up tight and high, ankle to calf or your Buddy or Boss's boots pressed hard against tense flesh, Boots are good to get close to, to hold and be held by even when it hurts. Your hardcock/cunt is convinced of that.

Polishing a Boot to a spit-shine returns the honor, gives the boot the Service, and Magnificent Looks that the Boot has earned by its power over you, sexually and mentally. If Boots are your most esteemed, valued possessions they should show it. There is no better way to display that esteem than by Spit-Shining Boots to the best of your ability and by keeping them Spit-Shined. Worn with pride they gleam with the black lure of military glamour, the focus of attention, eyed and admired by those who know.

I am wearing a pair of 10 inch high U.S.Army Combat Boots. They are ten eyelet to a side, rigidly ladder laced with Paratroop Boot laces. Pressed into the leather of the boot top you can read 12 R MB 12-71, size twelve regular issued in December, 1971. They gleam under a bright shine and are
a joy to look at. They are powerfully attractive, often stared at admiringly when I wear them. They display the pride I take in Boots and the pleasure their beauty gives to me. I hope they proclaim Military Boot Discipline Fetish!

The Military Spit Shine represents the highest achievement of a bootblacks skill. Producing that brilliant deep Black Glass Mirror finish on heavy Army grade 'Boots, Leather, Man's, Combat, Black', factory made to Military Specification is a job demanding patience, elbow grease, and perfectionist devotion. (A demanding Drill Instructor breathing down your neck or in your face can make up for the devotion as many recruit bootblacks can testify.) Most of us have to be our own D.I.s unless fortunate enough to bottom under the rule of an Miliaristic Top.

A great deal of arcane Spit Shine lore involving cotton balls, nylon stockings, after shave and so forth has evolved over the years. Generations of Enlisted Men have found newer, faster, better methods for spit-shines. I have tried all I have heard described. I would not want to separate any man wedded to a beloved technique learned in Boot Camp or Basic, and well honed. And of course any enslaved bootblack should seek direction from his Master and obey. But I know you could do worse in both time, effort, and outcome than the spitshine system I use and outline here.

In part it is adapted from the Guidebook for Marine NCOs but mostly learned from experience, by my own labors of love, shineing Combat Boots, Jump Boots, Low Quarter Dress Oxford Shoes and other Military Issue Footgear of various times and troops, mine and my Masters'.

Before you start, wash your hands. Oil and grease are the enemies of Shine. An oiled boot can not be polished. For this reason it is important to keep your hands or any other part of your body that might be in contact with the Boot, clean and free of skin oil.

The first step is to clean the Boot. I assume you are starting afresh on new, lightly broken in Boots or a pair that has had old layers of polish stripped off using lighter fluid and rags. If the Boot is caked with crud it needs a preliminary scrubdown with brush and water.

Past that there is no better instrument for boot cleaning than your tongue. The tongue can reach in the welt and seams and scrub out accumulated dust and dirt and by taste it will know when the seam is clean. It can lick the upper with broad strokes enjoying the savor of the leather. It can summon saliva to wetdown and scrub off the sole and heel, edge and bottom. It can work into eyelets and suck laces.

Bootlicking is an ideal way of demonstrating respect for a superior. "Bootlicker", "Asskisser", "Cocksucker" are all Topmale bywords for servility. For the submissive bootblack they are basic services of his office and performed with eager pleasure. Seize every opportunity to lick
Boots in public or private, working on your own boots alone at home or humbling yourself before the Boot shod feet of a Master in a Bar, a Soldier in the Park, or a Cop on the street. Anywhere, Bootlicking can fill you with the glowing good feeling of being in your right & proper place.

A Spit Shine takes time, five days is the minimum for the shine described below though ways exist to speed things up if required. To Begin: On each day for four days a layer of polish is spread on the Boot and allowed to dry 24 hours (Regular Kiwi Boot Polish is fine for this. Buy the big cans.)
This fills in the pores and minute cracks in the Bootleather and provides a base for the polishing. To spread the polish into the welt (where the upper and sole join) and into the seam edges it is necessary to use a small dauber or toothbrush. You may want to try working polish in with your
tongue. (I've never had much shining success applying polish with my tongue, lips or nose but the comic results of such attempts may tempt Tops to require it on occasion for their amusment and the submissives abasement. Walking around all day with your snout and mouth covered with Kiwi as a badge of servitude could be a healthy & entertaining exercise in humility and help a guy who is Boot shy to come out.)

For the upper leather and heel and sole edges, the Body of the Boot, use your fingers and rub the polish well into the leather, careful to smooth out any fine ridges left by fingerprints, leaving a sleek skin. The rich smell of the polish is a real high. The black mess of polish on fingers can be cleaned off with mineral spirits and a paper towel followed by soap and water. Tops who are sticklers for cleanliness are provided with a tough test of the bootblack's diligence in cleaning under fingernails.
A strapping on the palms of offending hands can be an appropriate enforcement of rule and satisfy a bottom's need for punishment.

After the Boot has dried overnight it should be given a light tongue dusting, no heavy licking here. Then a second coat is applied and allowed to dry. Carry out this procedure for four days, four coats of polish. After the final drying of the base coat you are ready to begin the spit
shine itself.

The equipment you will need consists of:

1. An All-cotton shine rag, the best are those made from an old T-shirt,
cut into hankerchief size squares. Be sure it is all cotton--a polyester
mix can strip off the polish you have so industriously applied,

2. Polish, preferably "Lincoln, stain, wax Polish, U.S.M.C. approved" or
"Kiwi Parade Gloss".

3. A source of water; I like to use a spray bottle to keep the hankerchief
damp and to moisten the surface of the polish as needed.
To begin, wet the rag and wring it out. You want it lightly damp but not
wet. Wrap a part of it around the first two fingers of your service hand
so the excess cloth can be held gathered between thumb and palm. Dip the
fingers in the moistened polish and start stroking the coated bootleather,
working a section at a time, Tongue, Toe, etc. You may be surprised at how
rapidly you bring up a shine if the Boot is well prepared. Keep at
it--that shine will become more and more hard shell brilliant with every
effort. Add Polish to the fingers as needed and spray dampen the cloth to
keep it from drying out. After the shine is getting slick you can wrap the
cloth around your hand and rub the boot with hard strokes to smooth the
surface to a glassy finish. It is amazing how mirror bright a boot can
become with diligent service. A single Jump Boot takes me about a half
hour to complete; so a pair takes an hour.

Though the results may dazzle and satisfy, it is always gratifying to give the Boots another final work over. Apply a light coat of the best polish and start over. This finish should blaze mirror bright and excite the admiration of all.

You will find that once applied a spit shine is easy to maintain. After wearing the boots a good tongue cleaning is called for to remove any polish that has flaked or scaled from the leather. This is especially likely to happen in creases where the leather flexes as the polish has been formed
into a hard cohesive layer and will flake where bent. When the finish is clouded or dim just apply a coat of your best polish and go to work with your damp cloth and all will be restored to near perfection.

You will occasionally cause inadvertent scrapes or scratches in the finish. To repair these I take a little mineral spirits on my finger and rub over the area of the scrape. This melts the old polish and allows you to spread it into the damaged area. Add some mineral spirits to your Kiwi to thin it and smooth more of that on to the area. When the marring is vanished, let the boot dry well, add some more of your finishing polish and bring the area back to a mirror gloss.