A crease in an area rug is a minor issue, but it can take away from the aesthetic of your floors and room overall. Sometimes an area rug will become creased after a move (rolled up for transport) or because a rolling chair ran over the fabric too many times in one spot. The sooner you work on removing the crease the better.
Turn the area rug on the side where the crease bends upward.
Warm an iron or steamer to the highest setting. Run the iron over the crease thoroughly---be careful not to let it sit too long in that one spot depending on the fabric so that it won't burn.
Spray the area rug with a commercial-grade wrinkle releaser product.
Pull the area rug taut (ask a buddy to help) and tape the edges of the rug to the floor. You can use cloth rug and carpet tape, a special tape with a strong adhesive to hold onto the fabric of the rug tightly.
Place a heavy flat object, like the top of a heavy table, on top of the area rug while it's still warm and slightly damp. Allow it to sit for at least six hours but preferably an entire day.
Toss a small area rug into a clothes dryer on the hottest setting to remove the creases as an alternative option.
Wash the area rug as another alternative and hang it out to dry in the sun.