I know that many people prefer to hose their mowers down with a garden hose. I admit I have done it. Still doing that is risky. If water gets into the wiring air filter or engine you could really do some damage. Hand washing with damp rag is a drag but also your safest bet.
Other buyers comment that the mower feels and look like a toy. It seems flimsy. But they also found it could handle child-swallowing yard growth. One of the coolest features of the Toro Recycler 22-inch Personal Pace Variable Speed Gas Walk Behind Self Propelled Lawn Mower that kept coming up in our research is the blade-brake clutch. This allows you to stop the blade without stopping the motor of the mower which is helpful for moving debris out of the way.
Some lawn mowers such as the Craftsman 37705 have a washout feature. It is essentially a garden hose fitting on top of the circular blade cover. This allows you to pump water into the blade assembly while running the engine. That action is designed to flush dirt and grass debris right out.