1.   Once you get the idea, repetition dulls the impact.

2.   The shovel stays stiff enough to pick up snow, but if you hit an obstruction, the spring dulls the impact of the scoop pushing into the handle.

3.   Critics say the amended version of the bill before the Cabinet would shield legislators and Cabinet ministers from full scrutiny and dull the impact of the measure.

4.   He said neighboring countries would continue to trade with Burma, dulling the impact of economic sanctions imposed by other nations.