To remove fat and food stains, you need soaps that will dissolve fat. The best alternative we have found for wool is lemon soap. In Norway, we recommend På Stell. It can be found in both a spray and a bar of soap. This stain remover won't damage the wool fibers, and efficiently dissolves the fat stains.
One doesn't always have lemon soap available when spillage occurs. In these cases, the best alternative is to use dish soap. This is also a good solution for the worst fat stains. Note that dish soap often contains enzymes that can damage the fibers if it is used too much.
The most efficient method of removing fat and food stains is to use the sink. Use stain remover (lemon soap or dish soap) on the spot and put the garment below the focet. The water should hit the stain directly so that it is running from the inside and out. The idea is that the stain is to go out the same way it came in. Usually the stains can be dissolved in warm water, but there are exceptions. Carbohydrates like starches and proteins like egg, milk and blood can be dissolved in cold water. On these types of stains you must avoid warm water, as this helps the stains stick to the material. Inspect the stain to figure out the correct method and temperature.