Lets take a look at an aspect of our impression that most of us never consider. I'm speaking specifically of the "tonsorial" side of things. We are all aware that men in mid-nineteeth America often wore facial hair. These styles involved mustaches, Van Dyke's (goatee's in modern parlance), beards of various lengths and sideburns ranging from ordinary styles to the voluminous muttonchop or "burnside" style. Frankly, soldiers in the field often sported facial hair because it was simply easier than shaving. Despite the challenges of shaving in the field, many men did so as evidenced by period images of cleanshaven troops. In fact, a statistical analysis of all existing images of soldiers from the period concluded that well over half were completely clean-shaven - particularly the enlisted men.
Let's look a little closer at the manly process of shaving. My goal here is to encourage you to give straight-razor shaving a try. You just might enjoy it once you get the hang of it. You'll acquire a new facet to your impression and I promise, you'll never have a closer shave. Shaving, regardless of the blade system involved is essentially scraping hair off the face. Fortunately, by our period, it had evolved to a very high level compared to some of the "systems" employed by men in previous centuries. In fact, many anthropologists believe the whole concept of face shaving evolved out of martial considerations. They have opined that shaving caught on when it became evident the bearded cavemen were often trounced by shaven cavemen. In fights, beards made a convenient handhold for the beardless ones, and many a bearded caveman's skull was then conveniently bashed in by his cleanshaven opponent.
Enough ancient history. Let's get to it. As stated, shaving was pretty well completely evolved by the mid-nineteenth century. The only significant remaining developments were safety razors around 1910, and electric razors in the 1920's.
With all that as background, Civil War soldiers who shaved probably didn't shave every day, but an interval of every two or three days would still serve to keep beards at bay and could probably be accomplished unless the unit was actively campaigning and moving extraordinarily frequently and quickly. We also know many simply chose to sit for a man in the unit who was handy with a razor and be shaved versus taking on the task himself. Let's look at what's required to shave yourself the way "they" did.
You'll need a razor, strop, a mug or cup in which to make lather, shaving soap, a shaving brush, and a mirror. I recommend you purchase a quality razor. They are usually available at knife shops also known as "cutlery" stores. Razors are available with handles made from natural materials which are completely authentic in appearance with the exception of some modern markings on the blade itself. Your call whether you wish to try to buff these out. Razors can also be purchased on line. You should probably expect to spend $40 - $50 on a good razor, which isn't much since with care, you'll be able to use it the rest of your life.
I'd avoid cheap Pakistani razors carried by some sutlers. They are fine for display purposes, but I wouldn't try to shave with them. Also, I'd be careful about trying to use that antique razor you have in your collection. The edge is critical and if it has ever been "dinged" or slightly misaligned, it can cut your face to ribbons. Its very difficult to straighten the edge of a razor that has been dropped or otherwise abused in this way. You can check for trueness of the edge by running your thumbnail lightly along the cutting edge and if it doesn't feel perfectly straight, don't even try to use it.
Now that you've settled on a razor, you'll need to strop it. This is nothing more than a fine realigning of the edge by a leather strap which is all the sharpening you'll need for months at a time. More about sharpening or "honing" later. Simply hang your strop (about $25.00 tops) at a convenient spot about waist level, extend it and hold it firmly, then strop your razor 8 - 10 strokes. You can even use the flesh side of your waistbelt for this purpose. Stropping must be done a particular way to be effective. Holding the open razor at a 90 degree angle to the strop, one simply lays the side of the blade down on the strop, and pulls the razor across the strop's surface. This is done by ensuring the back of the razor and its cutting edge are BOTH always in contact with the strop. Pull with the BACK EDGE of the razor leading, and the cutting edge trailing. At the end of the stroke, simply flip the blade over, rolling it over keeping the back always in contact with the strop and pull the other direction.
Again, with the back leading and edge trailing. Repeat this 8 - 10 times and you should be fine. Razors come from the factory shaving sharp and the stropping is all you'll need to do for quite some time.
Now its time to lather up. First, wash your face with soap and water. Then, simply employ a decent quality shaving soap available lots of places and a little hot water if you have it. "Williams" still makes a good shaving soap product, and it can be found at places like "Eckerds" and "CVS" drug stores. The stuff sells for about $1.50 and a single cake lasts about a month if used every day. You can use ordinary "bar" soap like "Ivory" in a pinch. Don't use aerosol shaving cream. It's not "slick" enough to work with this shaving method. Take your shaving brush, dampen the bristles, and with a stirring motion whip up a thick lather from the soap cake which you have placed in any mug or even your tin cup. Apply this liberally to your face. The lather performs two functions. First, it softens your beard as the hairs absorb the moisture. Secondly, the lather acts as a lubricant to allow the razor to move smoothly across your face. Let it sit on your face a minute or two before you begin shaving to give the lather time to help soften your beard.
Now its time to begin shaving. Open the razor with the handle about 270 degreesfrom the blade. Grasp the blade firmly but employ a light touch when you begin.With the blade at an angle no more than about 30 degrees from the plane formed by your face, begin to shave. Remember, you are essentially "scraping" off the whiskers, not "slicing" them away. TAKE YOUR TIME. With practice, you'll become adept, and your speed will improve, but don't get in a hurry in the beginning.
Start with the sides of your face, then move to your neck, and conclude with your chin. You can use your free hand to help pull the skin of your face taught which helps a lot. Always shave with the grain. Going against the direction the hair grows almost guarentees you'll cut yourself. If you find you need to go over a place more than once, feel free. You can also reapply lather in areas you didn't get close enough to suit on the first pass. It takes practice, but after a couple weeks you'll get the hang of it and nicks will be no more evident than shaving with a safety razor or disposable. You can deal with small nicks with a styptic pencil or block of alum (alum is more authentic) which instantly stops the bleeding. While I understand this may not be completely illustrative of the straight razor shaving process, if you still have questions, check around in your community. You can usually find a barber, particularly one over 60 who's still plying his trade, who can demonstrate good technique. I must also stress, even though this should be obvious, you MUST use a mirror and adequate light to do this safely. You can do it by candlelight, but you can't do it without a mirror unless you have a deathwish. As an aside, the scene from the movie "Glory" where Denzel Washington's character was shaving his head using his reflection on the bottom of a tin cup is pure balderdash.
When finished with your shaving session, carefully dry your razor and strop it again. Never put it away wet, as we know "rust ruins razors!" When completely dry, you can wipe it down with a bit of oil, or even fat, to help prevent rust as well, but be careful to wipe the thin film of oil or grease from the blade before you use it again.
Finally, at some point, stropping alone won't result in a keen enough edge anymore. Depending on the thickness of your beard, that is probably thirty shaves or so. At that point, you'll need to hone your razor. Either, return to the place you bought it and ask them to hone it for you, or, with a good quality whetstone, reverse the stropping procedure and carefully hone the edge. Honing is properly done by placing the razor down on the stone then lightly "push" the razor, this time edge first, across the length of the stone. At the end of the stroke, roll the razor over, all the while keeping the back of the razor in contact with the stone, and push the other side of the edge the length of the stone. Repeat a few times. Your razor should be shaving sharp again in about ten strokes. Light touch! Overdoing it can ruin the razor.
If you're game, try it. Practice at home, then take it to the field. I think you'll enjoy learning, and as I said at the outset, once you become accomplished, you'll never have a closer shave and won't be buying those expensive disposable shaving cartridges anymore. With practice, you'll be able to safely shave your face, in under ten minutes from start to finish -- which is a little bit longer than doing it with a modern disposable razor and a can of aerosol shaving cream, but far more rewarding!