Gonna disagree with KHatfull on this one. I use HOT water and dishsoap. Submerge the hood in hot water. You do not need to remove the lever from the body; you do need to remove the entire assembly from the handlebar. Lubricate the lever body with dishsoap and a bit of water. I install the rear of the lever body into the front of the hood. Then, rinse thoroughly with warm water, let dry and lubricate the pivots with a touch of grease.

Premature breakdown with Dawn and water? Nah.