Combine equal parts hot water and equal parts salt, and apply to your rug with a damp cloth. Although you don't need an ocean of the mixture applied (it will leave salt deposits that you'll need to re-rinse out later), you'll want to use enough that it will transfer from the rag or sponge to your rug. Give this trick a spot test to ensure that your particular rug can take the hot water, though most all rugs are able to hold up to this type of method. If you're worried, try using a dry towel placed over the areas to help blot any excess moisture back up.
(Image credits: Dabney Frake)