While there's no use crying over spilt milk, there's no sense wasting time cleaning it up, either. If milk isn't cleaned up immediately, it can result in that notorious sour-milk smell that no one wants to deal with. Quick thinking is the best way to combat both a stain and a foul smell in this situation. Armed with the proper know-how, you'll find that cleaning up spilt milk is really no big deal.
Blot the spill immediately with paper towels or a clean cloth to remove as much excess liquid as possible.
Scrub the area with a clean, damp cloth dipped in cold water to clean as much of the milk as possible out of the fibres.
Use a clean, dry cloth to wipe the area dry; alternate between the damp and the dry cloth a few times to ensure that all the milk has been cleaned up.
Sprinkle cornmeal over the affected area and allow it to sit for 20-30 minutes to absorb any residual moisture from the carpet.
Vacuum up the cornmeal and check for a stain. Repeat the process if necessary.
If the area stains, squeeze lemon juice on top of it and allow it to soak for at least 15 minutes before cleaning it up with a clean, damp cloth. Cover the area with baking soda and leave it overnight. Vacuum it up in the morning--both the stain and smell will be gone.