The flywheel on my briggs looks like its been under water for ages it real rusty can anybody tell me the best way to clean it without doing any harm .the flywheel is removed so I want to clean inside and out

Does it have a stator under the flywheel? Then just a wire brush, sand paper, wire wheel, etc will do.. if it has one, just try to clean the stator the best you can by hand, the outside, go crazy.. won't hurt it.