Wooden bowls and spoons were some of the more common eatingware among 18th-century soldiers. Examples of wooden spoons, cups, tankards and plates all survive in various museums and collections, and many of them are very similar to items commonly available today.1 Wood was readily available in military camps and could easily be whittled to shape by frugal soldiers.
Like cast iron, wooden bowls and eating utensils need to be seasoned to perform properly. Well-seasoned woodenware won't split or crack, and food doesn't stick to it making clean-up a breeze. Seasoning also imparts a great "patina" on the wood -- darkening it and bringing out the grain.
It takes very little time and attention to season wood. All you need is a bottle of good-quality vegetable oil and about five minutes of your time. Simply pour a small amount of oil into your hand and rub it into your bowl, plate or utensil. Repeat this process to coat all surfaces, paying particular attention to the "end grain" areas.
That's basically all there is to it. Repeat this process every few days for a week or two and your wood will be well-seasoned. Makers of today's fine woodenware recommend oiling their products: "once a day for a week, once a week for a month, once a month for a year, and once a year for a lifetime." I don't know that you have to strictly follow this schedule, but oiling your woodenware often and regularly -- especially when it's new -- is essential (leave your wooden items out on display in your home -- you will be more likely to remember to oil them).
Like cast iron, you should NOT use soap to wash up your wood -- it will draw-out the oils and you'll just have to season it all over again. Well-seasoned wood rinses clean with boiling water, which will also kill any bacteria that may be lurking on it, so you shouldn't need to use any soap.