Other items and supplies include a plastic drip tray motor oil and a container for waste oil. Often a large piece of cardboard is useful as well an old rag or cloth. Also know that this guide deals with push or self-propelled mowers not riding mowers. While some advice here applies they are another animal altogether.
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.
Consumer Reports recommends the Toro Recycler 20333 because of its very good ratings in ease of use handling side discharging and bagging and excellent mulching. The reviewer specifically liked the washout port for cleaning buildup under the sizable deck. The Wirecutter used to list the 20333 as the runner-up pick but supplanted it with the 20340 because of the newer models upright storage. However the reviewer still recommends the 20333 if the blade brake clutch is more important to you than compact storage.