Drop one ice cube in each of the stair spindle marks and let the ice melt slowly. Let the damp spots sit for 12 hours to give the carpet fibers time to loosen and bounce back.
Blot up the wet area with a clean cloth so that the carpet is just slightly damp.
Push the edge of a spoon between each of the carpet fibers. Agitate the fibers to raise them away from the carpet backing. Use the spoon to lift up the carpet fibers.
Repeat the process until the spindle marks are gone.
Wet a cloth with water and wring it out so that it is damp but is not dripping.
Lay the cloth over the spindle mark.
Heat an iron to medium heat and hold it 4 inches above the cloth. Keep it there for 60 seconds. This steam heats the cloth and slowly lifts the carpet fibers.
Lift the fibers with a metal spoon if needed.