After each mowing, wait until then engine cools and then use a hose to spray the clippings and grass debris that may be clinging to the underside of the deck of your mower (where the blade spins)

 Warning:
always make sure that your mower engine has stopped and if you have to put your hands near the deck that you have disconnected the spark-plug cable from the plug prior to cleaning. You can reconnect after cleaning. This will keep grass clippings from building up in the deck of the mower and help prevent clogging while bagging. This will also allow ample room for the mulching to take place while mowing.