Do You Need to Wash Your Car''s Undercarriage? | HowStuffWorks
May 07, 2019· If you prefer to wash your car''s undercarriage at home instead of at a car wash, Beasley''s suggests you invest in a pressure washer and a good degreasing agent. The pressure washer can easily reach areas that you can''t — or wouldn''t want to — reach by hand, and the degreaser will ensure all the surfaces are rinsed clean.