Yes! It’s when you give the vehicle exterior a complete wash using wheel acid. Most car care product companies mixes are different some more stronger than others. If I didn’t mix the wheel acid myself and it was already pre mixed. I usually wash the vehicle exterior with soap and why soap is still on vehicle. I wash vehicle exterior with wheel acid. It’s very important not to get wheel acid on none chrome trim pieces, door mirror glasses and wiper blades arms attachments. I have several videos of me performing Exterior Acid Chemical Baths