Ok I said in the Militaria thread (a long time ago) that I now possess an american WWII officer's overcoat.
question is, can I take it to the dry cleaners or should I wash it manually? Ironing is I presume as usual.
Mudra suggested dry cleaning but it can actually damage wool (especially older products)
from my years of maintaining tunics, I have found that spot cleaning and a fabric brush are much more effective than attempting dry cleaning (which actually uses wet chemicals).
On an inside (or inconspicuous location), try using a mild solution of wool-safe laundry detergent (woolite is my brand) that has been mixed with some lukewarm water. Rub/blot gently with a soft cloth (that doesn't give off fabric pills) and if that cleans up well enough for you, then continue on with the rest of the material. use the fabric brush on areas that have fabric discolouration or on dry (non-setting stains) like mud or maybe some powder from a bag of chips.
Hang the clothing to dry (preferably in the sunshine) and only iron if you haven't been able to hang away the creases. Do not use starches and make sure the setting is on lower Wool with low power-steam. Never apply the iron to one location for too long, instead be patient and revisit the locations that look less desirable to you after the fabric has cooled somewhat.
if your iron doesn't have a steam setting, you can also use a thick towel which is thoroughly soaked and place the wet towel under the areas that you wish to iron. It draws the steam through the fabric in a gentle fashion, as long as your iron is not too hot.
These tips are straight from veteran's who still wear their original uniforms and from my personal experience of maintaining my collection of Highland attire. It works, costs less than a dry cleaner and has less risk of damaging the fabric. Certain stains will never come out, so be advised and don't work he fabric to death or complain to the dry cleaner (if you use one)